List of Copyright holders
=========================
- Copyright (C) 1989,1991-2017 Free Software Foundation, Inc.
+ Copyright (C) 1989,1991-2018 Free Software Foundation, Inc.
Copyright (C) 1994 X Consortium
Copyright (C) 1996 L. Peter Deutsch
Copyright (C) 1997 Werner Koch
Copyright (C) 1996-2006 Peter Gutmann, Matt Thomlinson and Blake Coverett
Copyright (C) 2003 Nikos Mavroyanopoulos
Copyright (C) 2006-2007 NTT (Nippon Telegraph and Telephone Corporation)
- Copyright (C) 2012-2017 g10 Code GmbH
+ Copyright (C) 2012-2018 g10 Code GmbH
Copyright (C) 2012 Simon Josefsson, Niels Möller
Copyright (c) 2012 Intel Corporation
Copyright (C) 2013 Christian Grothoff
+2018-06-13 Werner Koch <wk@gnupg.org>
+
+ Release 1.8.3.
+ + commit 5600d2d6b23640b0114655214f18959ee81fe58e
+
+
+2018-06-13 NIIBE Yutaka <gniibe@fsij.org>
+
+ ecc: Add blinding for ECDSA.
+ + commit 9be06c6b2e5c96edf40e566bbf51d44c4d46fb07
+ * cipher/ecc-ecdsa.c (_gcry_ecc_ecdsa_sign): Blind secret D with
+ randomized nonce B.
+
+2018-06-11 Werner Koch <wk@gnupg.org>
+
+ ecc: Improve gcry_mpi_ec_curve_point.
+ + commit 846f8fe8b3be6d235592db184361df1bc2b07a8a
+ * mpi/ec.c (_gcry_mpi_ec_curve_point): Check range of coordinates.
+ * tests/t-mpi-point.c (point_on_curve): New.
+
+ mpi: New internal function _gcry_mpi_cmpabs.
+ + commit 54620a27f4503e703e219e6e11c4be14ce4e3d35
+ * mpi/mpi-cmp.c (_gcry_mpi_cmp): Factor out to ...
+ (do_mpi_cmp): New. Add arg absmode.
+ (_gcry_mpi_cmpabs): New.
+ * src/gcrypt-int.h (mpi_cmpabs): New macro.
+
+ (cherry picked from commit 6606ae44e0de1069b29dd4215ee9748280940e1b)
+
+2018-04-29 Werner Koch <wk@gnupg.org>
+
+ build: Convince gcc not to delete NULL ptr checks.
+ + commit 1a0289daa408773e1a6cefb2562288245f49651c
+ * configure.ac: Try to use -fno-delete-null-pointer-checks.
+
+ (cherry picked from commit 61dbb7c08ab11c10060e193b52e3e1d2ec6dd062)
+
+ prime: Avoid rare assertion failure in gcry_prime_check.
+ + commit c5bed9df96337b1553cdcd4a85eec10e78b4d14a
+ * cipher/primegen.c (is_prime): Don't fail on the assert X > 1.
+
+2018-04-17 Jussi Kivilinna <jussi.kivilinna@iki.fi>
+
+ Make BMI2 inline assembly check more robust.
+ + commit 22db6237de00cafb85c0112073b55d0d750e6b03
+ * configure.ac (gcry_cv_gcc_inline_asm_bmi2): New assembly test.
+
+2018-04-17 Stephan Mueller <smueller@chronox.de>
+
+ AES-KW: fix in-place encryption.
+ + commit bbf88f0e9d481486ceca079e2611e84db8d039c7
+ * cipher/cipher-aeswrap.c: move memmove call before KW IV setting
+
+2018-04-17 Werner Koch <wk@gnupg.org>
+
+ mpi: Fix for buidling for MIPS64 with Clang.
+ + commit a0e016e29409ccd78966a5eb82dea236ad44d9c9
+ * mpi/longlong.h [MIPS64][__clang__]: Use the C version like we
+ already do for 32 bit MIPS.
+
+2018-04-17 NIIBE Yutaka <gniibe@fsij.org>
+
+ hmac: Use xtrymalloc.
+ + commit 06fdc074eb29faf584ffd13feea4c063936446fb
+ * src/hmac256.c (_gcry_hmac256_new): Use xtrymalloc.
+ (_gcry_hmac256_file): Likewise.
+
+ random: Protect another use of jent_rng_collector.
+ + commit 0da4a237661cd273303ae6baaaba2d9f6292b990
+ * random/rndjent.c (_gcry_rndjent_get_version): Lock the access.
+
+ (cherry picked from commit 0de2a22fcf6607d0aecb550feefa414cee3731b2)
+
+2018-04-17 Martin Storsjö <martin@martin.st>
+
+ random: Don't assume that _WIN64 implies x86_64.
+ + commit e1695a8f6ca1135d777450cf9ce64628b0778ccb
+ * random/rndw32.c: Change _WIN64 ifdef into __x86_64__.
+
+2018-04-17 Jussi Kivilinna <jussi.kivilinna@iki.fi>
+
+ Improve constant-time buffer compare.
+ + commit 4e11e9d988181cf9cd87c7c86fa8e7a0f643a573
+ * cipher/bufhelp.h (buf_eq_const): Rewrite logic.
+
+ Fix incorrect counter overflow handling for GCM.
+ + commit 0a391b259adcd7ea734dc03c2048a135e018166d
+ * cipher/cipher-gcm.c (gcm_ctr_encrypt): New function to handle
+ 32-bit CTR increment for GCM.
+ (_gcry_cipher_gcm_encrypt, _gcry_cipher_gcm_decrypt): Do not use
+ generic CTR implementation directly, use gcm_ctr_encrypt instead.
+ * tests/basic.c (_check_gcm_cipher): Add test-vectors for 32-bit
+ CTR overflow.
+ (check_gcm_cipher): Add 'split input to 15 bytes and 17 bytes'
+ test-runs.
+
+ doc: fix double "See" in front of reference.
+ + commit c114ffd6da837e7aace318e37bbcf9325dd985b7
+ * doc/gcrypt.texi: Change @xref to @ref when text already has 'see' in
+ the front.
+
+2017-12-13 Werner Koch <wk@gnupg.org>
+
+ Release 1.8.2.
+ + commit eb84e429950b6a61c00112e70a584940c1d352e4
+
+
+2017-11-24 Werner Koch <wk@gnupg.org>
+
+ sexp: Avoid a fatal error in case of ENOMEM in called functions.
+ + commit 59df8d6295426d0a9cf7646c381df2ea29fdb8c5
+ * src/sexp.c (do_vsexp_sscan): Replace BUG() by a proper error
+ return. Replace sprintf by snprintf.
+ (convert_to_hex): Replace sprintf by snprintf.
+ (convert_to_string): Ditto.
+ (_gcry_sexp_sprint): Ditto.
+
+2017-11-23 Werner Koch <wk@gnupg.org>
+
+ api: Add auto expand secmem feature.
+ + commit f4582f8c429f22b18f8ca8a40660a91d721f5c96
+ * src/global.c (_gcry_vcontrol): Implement control value 78.
+ * src/secmem.c (auto_expand): New var.
+ (_gcry_secmem_set_auto_expand): New.
+ (_gcry_secmem_malloc_internal): Act upon AUTO_EXPAND.
+
+2017-11-14 NIIBE Yutaka <gniibe@fsij.org>
+
+ tests: Add HAVE_MMAP check for MinGW.
+ + commit 334e1a1cfc8f59db765a0bff0ca29090aa11b0f6
+ * tests/t-secmem.c (main): Conditionalize with HAVE_MMAP.
+
+2017-11-09 NIIBE Yutaka <gniibe@fsij.org>
+
+ Fix secmem test for machine with larger page.
+ + commit da127f7505ff7681fc9dbfbf332121d2998e88aa
+ * tests/t-secmem.c (main): Detect page size and setup chunk size.
+ * src/secmem.c (init_pool): Simplify the expression.
+
2017-08-27 Werner Koch <wk@gnupg.org>
Release 1.8.1.
+Noteworthy changes in version 1.8.3 (2018-06-13) [C22/A2/R3]
+------------------------------------------------
+
+ * Bug fixes:
+
+ - Use blinding for ECDSA signing to mitigate a novel side-channel
+ attack. [#4011,CVE-2018-0495]
+
+ - Fix incorrect counter overflow handling for GCM when using an IV
+ size other than 96 bit. [#3764]
+
+ - Fix incorrect output of AES-keywrap mode for in-place encryption
+ on some platforms.
+
+ - Fix the gcry_mpi_ec_curve_point point validation function.
+
+ - Fix rare assertion failure in gcry_prime_check.
+
+
+Noteworthy changes in version 1.8.2 (2017-12-13) [C22/A2/R2]
+------------------------------------------------
+
+ * Bug fixes:
+
+ - Do not use /dev/srandom on OpenBSD.
+
+ - Fix test suite failure on systems with large pages. [#3351]
+
+ - Fix test suite to not use mmap on Windows.
+
+ - Fix fatal out of secure memory status in the s-expression parser
+ on heavy loaded systems.
+
+ * Other:
+
+ - Backport the auto expand secmem feature from master for use by
+ the forthcoming GnuPG 2.2.4.
+
+
Noteworthy changes in version 1.8.1 (2017-08-27) [C22/A2/R1]
------------------------------------------------
Libgcrypt - The GNU Crypto Library
------------------------------------
- Version 1.7
+ Version 1.8
- Copyright (C) 1989,1991-2017 Free Software Foundation, Inc.
- Copyright (C) 2012-2017 g10 Code GmbH
- Copyright (C) 2013-2017 Jussi Kivilinna
+ Copyright (C) 1989,1991-2018 Free Software Foundation, Inc.
+ Copyright (C) 2012-2018 g10 Code GmbH
+ Copyright (C) 2013-2018 Jussi Kivilinna
Libgcrypt is free software. See the file AUTHORS for full copying
notices, and LICENSES for notices about contributions that require
{
const byte *a = _a;
const byte *b = _b;
- size_t diff, i;
+ int ab, ba;
+ size_t i;
/* Constant-time compare. */
- for (i = 0, diff = 0; i < len; i++)
- diff -= !!(a[i] - b[i]);
+ for (i = 0, ab = 0, ba = 0; i < len; i++)
+ {
+ /* If a[i] != b[i], either ab or ba will be negative. */
+ ab |= a[i] - b[i];
+ ba |= b[i] - a[i];
+ }
- return !diff;
+ /* 'ab | ba' is negative when buffers are not equal. */
+ return (ab | ba) >= 0;
}
a = outbuf; /* We store A directly in OUTBUF. */
b = c->u_ctr.ctr; /* B is also used to concatenate stuff. */
+ /* Copy the inbuf to the outbuf. */
+ memmove (r+8, inbuf, inbuflen);
+
/* If an IV has been set we use that IV as the Alternative Initial
Value; if it has not been set we use the standard value. */
if (c->marks.iv)
else
memset (a, 0xa6, 8);
- /* Copy the inbuf to the outbuf. */
- memmove (r+8, inbuf, inbuflen);
-
memset (t, 0, sizeof t); /* t := 0. */
for (j = 0; j <= 5; j++)
/* cipher-gcm.c - Generic Galois Counter Mode implementation
* Copyright (C) 2013 Dmitry Eremin-Solenikov
- * Copyright (C) 2013 Jussi Kivilinna <jussi.kivilinna@iki.fi>
+ * Copyright (C) 2013, 2018 Jussi Kivilinna <jussi.kivilinna@iki.fi>
*
* This file is part of Libgcrypt.
*
}
+static gcry_err_code_t
+gcm_ctr_encrypt (gcry_cipher_hd_t c, byte *outbuf, size_t outbuflen,
+ const byte *inbuf, size_t inbuflen)
+{
+ gcry_err_code_t err = 0;
+
+ while (inbuflen)
+ {
+ u32 nblocks_to_overflow;
+ u32 num_ctr_increments;
+ u32 curr_ctr_low;
+ size_t currlen = inbuflen;
+ byte ctr_copy[GCRY_GCM_BLOCK_LEN];
+ int fix_ctr = 0;
+
+ /* GCM CTR increments only least significant 32-bits, without carry
+ * to upper 96-bits of counter. Using generic CTR implementation
+ * directly would carry 32-bit overflow to upper 96-bit. Detect
+ * if input length is long enough to cause overflow, and limit
+ * input length so that CTR overflow happen but updated CTR value is
+ * not used to encrypt further input. After overflow, upper 96 bits
+ * of CTR are restored to cancel out modification done by generic CTR
+ * encryption. */
+
+ if (inbuflen > c->unused)
+ {
+ curr_ctr_low = gcm_add32_be128 (c->u_ctr.ctr, 0);
+
+ /* Number of CTR increments this inbuflen would cause. */
+ num_ctr_increments = (inbuflen - c->unused) / GCRY_GCM_BLOCK_LEN +
+ !!((inbuflen - c->unused) % GCRY_GCM_BLOCK_LEN);
+
+ if ((u32)(num_ctr_increments + curr_ctr_low) < curr_ctr_low)
+ {
+ nblocks_to_overflow = 0xffffffffU - curr_ctr_low + 1;
+ currlen = nblocks_to_overflow * GCRY_GCM_BLOCK_LEN + c->unused;
+ if (currlen > inbuflen)
+ {
+ currlen = inbuflen;
+ }
+
+ fix_ctr = 1;
+ buf_cpy(ctr_copy, c->u_ctr.ctr, GCRY_GCM_BLOCK_LEN);
+ }
+ }
+
+ err = _gcry_cipher_ctr_encrypt(c, outbuf, outbuflen, inbuf, currlen);
+ if (err != 0)
+ return err;
+
+ if (fix_ctr)
+ {
+ /* Lower 32-bits of CTR should now be zero. */
+ gcry_assert(gcm_add32_be128 (c->u_ctr.ctr, 0) == 0);
+
+ /* Restore upper part of CTR. */
+ buf_cpy(c->u_ctr.ctr, ctr_copy, GCRY_GCM_BLOCK_LEN - sizeof(u32));
+
+ wipememory(ctr_copy, sizeof(ctr_copy));
+ }
+
+ inbuflen -= currlen;
+ inbuf += currlen;
+ outbuflen -= currlen;
+ outbuf += currlen;
+ }
+
+ return err;
+}
+
+
gcry_err_code_t
_gcry_cipher_gcm_encrypt (gcry_cipher_hd_t c,
byte *outbuf, size_t outbuflen,
return GPG_ERR_INV_LENGTH;
}
- err = _gcry_cipher_ctr_encrypt(c, outbuf, outbuflen, inbuf, inbuflen);
+ err = gcm_ctr_encrypt(c, outbuf, outbuflen, inbuf, inbuflen);
if (err != 0)
return err;
do_ghash_buf(c, c->u_mode.gcm.u_tag.tag, inbuf, inbuflen, 0);
- return _gcry_cipher_ctr_encrypt(c, outbuf, outbuflen, inbuf, inbuflen);
+ return gcm_ctr_encrypt(c, outbuf, outbuflen, inbuf, inbuflen);
}
const void *abuf;
unsigned int abits, qbits;
mpi_ec_t ctx;
+ gcry_mpi_t b; /* Random number needed for blinding. */
+ gcry_mpi_t bi; /* multiplicative inverse of B. */
if (DBG_CIPHER)
log_mpidump ("ecdsa sign hash ", input );
if (rc)
return rc;
+ b = mpi_snew (qbits);
+ bi = mpi_snew (qbits);
+ do
+ {
+ _gcry_mpi_randomize (b, qbits, GCRY_WEAK_RANDOM);
+ mpi_mod (b, b, skey->E.n);
+ }
+ while (!mpi_invm (bi, b, skey->E.n));
+
k = NULL;
dr = mpi_alloc (0);
sum = mpi_alloc (0);
}
while (!mpi_cmp_ui (r, 0));
- mpi_mulm (dr, skey->d, r, skey->E.n); /* dr = d*r mod n */
- mpi_addm (sum, hash, dr, skey->E.n); /* sum = hash + (d*r) mod n */
+ mpi_mulm (dr, b, skey->d, skey->E.n);
+ mpi_mulm (dr, dr, r, skey->E.n); /* dr = d*r mod n (blinded with b) */
+ mpi_mulm (sum, b, hash, skey->E.n);
+ mpi_addm (sum, sum, dr, skey->E.n); /* sum = hash + (d*r) mod n (blinded with b) */
+ mpi_mulm (sum, bi, sum, skey->E.n); /* undo blinding by b^-1 */
mpi_invm (k_1, k, skey->E.n); /* k_1 = k^(-1) mod n */
mpi_mulm (s, k_1, sum, skey->E.n); /* s = k^(-1)*(hash+(d*r)) mod n */
}
}
leave:
+ mpi_free (b);
+ mpi_free (bi);
_gcry_mpi_ec_free (ctx);
point_free (&I);
mpi_free (x);
}
else
{
- _gcry_mpi_randomize( x, nbits, GCRY_WEAK_RANDOM );
-
- /* Make sure that the number is smaller than the prime and
- keep the randomness of the high bit. */
- if ( mpi_test_bit ( x, nbits-2) )
+ /* We need to loop to avoid an X with value 0 or 1. */
+ do
{
- mpi_set_highbit ( x, nbits-2); /* Clear all higher bits. */
- }
- else
- {
- mpi_set_highbit( x, nbits-2 );
- mpi_clear_bit( x, nbits-2 );
+ _gcry_mpi_randomize (x, nbits, GCRY_WEAK_RANDOM);
+
+ /* Make sure that the number is smaller than the prime
+ * and keep the randomness of the high bit. */
+ if (mpi_test_bit (x, nbits-2))
+ {
+ mpi_set_highbit (x, nbits-2); /* Clear all higher bits. */
+ }
+ else
+ {
+ mpi_set_highbit (x, nbits-2);
+ mpi_clear_bit (x, nbits-2);
+ }
}
- gcry_assert (mpi_cmp (x, nminus1) < 0 && mpi_cmp_ui (x, 1) > 0);
+ while (mpi_cmp_ui (x, 1) <= 0);
+ gcry_assert (mpi_cmp (x, nminus1) < 0);
}
mpi_powm ( y, x, q, n);
if ( mpi_cmp_ui(y, 1) && mpi_cmp( y, nminus1 ) )
static const char blurb[] =
"\n\n"
"This is Libgcrypt " PACKAGE_VERSION " - The GNU Crypto Library\n"
- "Copyright (C) 2000-2017 Free Software Foundation, Inc.\n"
- "Copyright (C) 2012-2017 g10 Code GmbH\n"
- "Copyright (C) 2013-2017 Jussi Kivilinna\n"
+ "Copyright (C) 2000-2018 Free Software Foundation, Inc.\n"
+ "Copyright (C) 2012-2018 g10 Code GmbH\n"
+ "Copyright (C) 2013-2018 Jussi Kivilinna\n"
"\n"
"(" BUILD_REVISION " " BUILD_TIMESTAMP ")\n"
"\n\n";
#! /bin/sh
# From configure.ac Revision.
# Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for libgcrypt 1.8.1.
+# Generated by GNU Autoconf 2.69 for libgcrypt 1.8.3.
#
# Report bugs to <http://bugs.gnupg.org>.
#
# Identity of this package.
PACKAGE_NAME='libgcrypt'
PACKAGE_TARNAME='libgcrypt'
-PACKAGE_VERSION='1.8.1'
-PACKAGE_STRING='libgcrypt 1.8.1'
+PACKAGE_VERSION='1.8.3'
+PACKAGE_STRING='libgcrypt 1.8.3'
PACKAGE_BUGREPORT='http://bugs.gnupg.org'
PACKAGE_URL=''
# Omit some internal or obsolete options to make the list less imposing.
# This message is too long to be a string in the A/UX 3.1 sh.
cat <<_ACEOF
-\`configure' configures libgcrypt 1.8.1 to adapt to many kinds of systems.
+\`configure' configures libgcrypt 1.8.3 to adapt to many kinds of systems.
Usage: $0 [OPTION]... [VAR=VALUE]...
if test -n "$ac_init_help"; then
case $ac_init_help in
- short | recursive ) echo "Configuration of libgcrypt 1.8.1:";;
+ short | recursive ) echo "Configuration of libgcrypt 1.8.3:";;
esac
cat <<\_ACEOF
test -n "$ac_init_help" && exit $ac_status
if $ac_init_version; then
cat <<\_ACEOF
-libgcrypt configure 1.8.1
+libgcrypt configure 1.8.3
generated by GNU Autoconf 2.69
Copyright (C) 2012 Free Software Foundation, Inc.
This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.
-It was created by libgcrypt $as_me 1.8.1, which was
+It was created by libgcrypt $as_me 1.8.3, which was
generated by GNU Autoconf 2.69. Invocation command line was
$ $0 $@
# (No interfaces changed: REVISION++)
LIBGCRYPT_LT_CURRENT=22
LIBGCRYPT_LT_AGE=2
-LIBGCRYPT_LT_REVISION=1
+LIBGCRYPT_LT_REVISION=3
# If the API is changed in an incompatible way: increment the next counter.
# Define the identity of the package.
PACKAGE='libgcrypt'
- VERSION='1.8.1'
+ VERSION='1.8.3'
cat >>confdefs.h <<_ACEOF
#define VERSION "$VERSION"
_ACEOF
-VERSION_NUMBER=0x010801
+VERSION_NUMBER=0x010803
;;
esac
-#
-# Figure out the name of the random device
-#
-case "${host}" in
- *-openbsd*)
- NAME_OF_DEV_RANDOM="/dev/srandom"
- NAME_OF_DEV_URANDOM="/dev/urandom"
- ;;
-
- *)
- NAME_OF_DEV_RANDOM="/dev/random"
- NAME_OF_DEV_URANDOM="/dev/urandom"
- ;;
-esac
-
+NAME_OF_DEV_RANDOM="/dev/random"
+NAME_OF_DEV_URANDOM="/dev/urandom"
# Check whether --enable-endian-check was given.
if test "${enable_endian_check+set}" = set; then :
gcry_cv_gcc_inline_asm_bmi2=no
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
-void a(void) {
- __asm__("rorxl \$23, %%eax, %%edx\\n\\t":::"memory");
+unsigned int a(unsigned int x, unsigned int y) {
+ unsigned int tmp1, tmp2;
+ asm ("rorxl %2, %1, %0"
+ : "=r" (tmp1)
+ : "rm0" (x), "J" (32 - ((23) & 31)));
+ asm ("andnl %2, %1, %0"
+ : "=r" (tmp2)
+ : "r0" (x), "rm" (y));
+ return tmp1 + tmp2;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for cc features" >&5
+$as_echo "$as_me: checking for cc features" >&6;}
# CFLAGS mangling when using gcc.
if test "$GCC" = yes; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking if gcc supports -fno-delete-null-pointer-checks" >&5
+$as_echo_n "checking if gcc supports -fno-delete-null-pointer-checks... " >&6; }
+ _gcc_cflags_save=$CFLAGS
+ CFLAGS="-fno-delete-null-pointer-checks"
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+int
+main ()
+{
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+ _gcc_wopt=yes
+else
+ _gcc_wopt=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: $_gcc_wopt" >&5
+$as_echo "$_gcc_wopt" >&6; }
+ CFLAGS=$_gcc_cflags_save;
+ if test x"$_gcc_wopt" = xyes ; then
+ CFLAGS="$CFLAGS -fno-delete-null-pointer-checks"
+ fi
+
CFLAGS="$CFLAGS -Wall"
if test "$USE_MAINTAINER_MODE" = "yes"; then
CFLAGS="$CFLAGS -Wcast-align -Wshadow -Wstrict-prototypes"
CFLAGS="$CFLAGS -Wpointer-arith"
fi
fi
-
fi
# Check whether as(1) supports a noeexecstack feature. This test
#
# Provide information about the build.
#
-BUILD_REVISION="80fd861"
+BUILD_REVISION="5600d2d"
cat >>confdefs.h <<_ACEOF
BUILD_FILEVERSION=`echo "$VERSION" | sed 's/\([0-9.]*\).*/\1./;s/\./,/g'`
-BUILD_FILEVERSION="${BUILD_FILEVERSION}33021"
+BUILD_FILEVERSION="${BUILD_FILEVERSION}22016"
# Check whether --enable-build-timestamp was given.
# report actual input values of CONFIG_FILES etc. instead of their
# values after options handling.
ac_log="
-This file was extended by libgcrypt $as_me 1.8.1, which was
+This file was extended by libgcrypt $as_me 1.8.3, which was
generated by GNU Autoconf 2.69. Invocation command line was
CONFIG_FILES = $CONFIG_FILES
cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
ac_cs_version="\\
-libgcrypt config.status 1.8.1
+libgcrypt config.status 1.8.3
configured by $0, generated by GNU Autoconf 2.69,
with options \\"\$ac_cs_config\\"
# for the LT versions.
m4_define(mym4_version_major, [1])
m4_define(mym4_version_minor, [8])
-m4_define(mym4_version_micro, [1])
+m4_define(mym4_version_micro, [3])
# Below is m4 magic to extract and compute the revision number, the
# decimalized short revision number, a beta version string, and a flag
# (No interfaces changed: REVISION++)
LIBGCRYPT_LT_CURRENT=22
LIBGCRYPT_LT_AGE=2
-LIBGCRYPT_LT_REVISION=1
+LIBGCRYPT_LT_REVISION=3
# If the API is changed in an incompatible way: increment the next counter.
;;
esac
-#
-# Figure out the name of the random device
-#
-case "${host}" in
- *-openbsd*)
- NAME_OF_DEV_RANDOM="/dev/srandom"
- NAME_OF_DEV_URANDOM="/dev/urandom"
- ;;
-
- *)
- NAME_OF_DEV_RANDOM="/dev/random"
- NAME_OF_DEV_URANDOM="/dev/urandom"
- ;;
-esac
-
+NAME_OF_DEV_RANDOM="/dev/random"
+NAME_OF_DEV_URANDOM="/dev/urandom"
AC_ARG_ENABLE(endian-check,
AC_HELP_STRING([--disable-endian-check],
else
gcry_cv_gcc_inline_asm_bmi2=no
AC_COMPILE_IFELSE([AC_LANG_SOURCE(
- [[void a(void) {
- __asm__("rorxl \$23, %%eax, %%edx\\n\\t":::"memory");
+ [[unsigned int a(unsigned int x, unsigned int y) {
+ unsigned int tmp1, tmp2;
+ asm ("rorxl %2, %1, %0"
+ : "=r" (tmp1)
+ : "rm0" (x), "J" (32 - ((23) & 31)));
+ asm ("andnl %2, %1, %0"
+ : "=r" (tmp2)
+ : "r0" (x), "rm" (y));
+ return tmp1 + tmp2;
}]])],
[gcry_cv_gcc_inline_asm_bmi2=yes])
fi])
CFLAGS=`echo $CFLAGS | sed 's/-O[[0-9]]//'`
fi])
+AC_MSG_NOTICE([checking for cc features])
# CFLAGS mangling when using gcc.
if test "$GCC" = yes; then
+ AC_MSG_CHECKING([if gcc supports -fno-delete-null-pointer-checks])
+ _gcc_cflags_save=$CFLAGS
+ CFLAGS="-fno-delete-null-pointer-checks"
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],_gcc_wopt=yes,_gcc_wopt=no)
+ AC_MSG_RESULT($_gcc_wopt)
+ CFLAGS=$_gcc_cflags_save;
+ if test x"$_gcc_wopt" = xyes ; then
+ CFLAGS="$CFLAGS -fno-delete-null-pointer-checks"
+ fi
+
CFLAGS="$CFLAGS -Wall"
if test "$USE_MAINTAINER_MODE" = "yes"; then
CFLAGS="$CFLAGS -Wcast-align -Wshadow -Wstrict-prototypes"
CFLAGS="$CFLAGS -Wpointer-arith"
fi
fi
-
fi
# Check whether as(1) supports a noeexecstack feature. This test
%!PS-Adobe-3.0 EPSF-3.0
-%%Title: /home/wk/s/libgcrypt/doc/fips-fsm.fig
+%%Title: /home/wk/s/libgcrypt-1.8/doc/fips-fsm.fig
%%Creator: fig2dev Version 3.2 Patchlevel 5e
-%%CreationDate: Tue Jan 6 19:07:13 2015
+%%CreationDate: Thu Nov 23 19:46:17 2017
%%BoundingBox: 0 0 497 579
%Magnification: 1.0000
%%EndComments
This is gcrypt.info, produced by makeinfo version 6.3 from gcrypt.texi.
-This manual is for Libgcrypt (version 1.8.1, 18 July 2017), which is
+This manual is for Libgcrypt (version 1.8.3, 13 June 2018), which is
GNU's library of cryptographic building blocks.
Copyright (C) 2000, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2011, 2012
END-INFO-DIR-ENTRY
\1f
-File: gcrypt.info, Node: Top, Next: Introduction, Up: (dir)
-
-The Libgcrypt Library
-*********************
-
-This manual is for Libgcrypt (version 1.8.1, 18 July 2017), which is
-GNU's library of cryptographic building blocks.
-
-Copyright (C) 2000, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2011, 2012
-Free Software Foundation, Inc.
-Copyright (C) 2012, 2013, 2016, 2017 g10 Code GmbH
-
- Permission is granted to copy, distribute and/or modify this
- document under the terms of the GNU General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version. The text of the
- license can be found in the section entitled "GNU General Public
- License".
-
-* Menu:
-
-* Introduction:: What is Libgcrypt.
-* Preparation:: What you should do before using the library.
-* Generalities:: General library functions and data types.
-* Handler Functions:: Working with handler functions.
-* Symmetric cryptography:: How to use symmetric cryptography.
-* Public Key cryptography:: How to use public key cryptography.
-* Hashing:: How to use hash algorithms.
-* Message Authentication Codes:: How to use MAC algorithms.
-* Key Derivation:: How to derive keys from strings
-* Random Numbers:: How to work with random numbers.
-* S-expressions:: How to manage S-expressions.
-* MPI library:: How to work with multi-precision-integers.
-* Prime numbers:: How to use the Prime number related functions.
-* Utilities:: Utility functions.
-* Tools:: Utility tools.
-* Configuration:: Configuration files and environment variables.
-* Architecture:: How Libgcrypt works internally.
-
-Appendices
-
-* Self-Tests:: Description of the self-tests.
-* FIPS Mode:: Description of the FIPS mode.
-* Library Copying:: The GNU Lesser General Public License
- says how you can copy and share Libgcrypt.
-* Copying:: The GNU General Public License says how you
- can copy and share some parts of Libgcrypt.
-
-Indices
-
-* Figures and Tables:: Index of figures and tables.
-* Concept Index:: Index of concepts and programs.
-* Function and Data Index:: Index of functions, variables and data types.
-
-\1f
-File: gcrypt.info, Node: Introduction, Next: Preparation, Prev: Top, Up: Top
-
-1 Introduction
-**************
-
-Libgcrypt is a library providing cryptographic building blocks.
-
-* Menu:
-
-* Getting Started:: How to use this manual.
-* Features:: A glance at Libgcrypt's features.
-* Overview:: Overview about the library.
-
-\1f
-File: gcrypt.info, Node: Getting Started, Next: Features, Up: Introduction
-
-1.1 Getting Started
-===================
-
-This manual documents the Libgcrypt library application programming
-interface (API). All functions and data types provided by the library
-are explained.
-
-The reader is assumed to possess basic knowledge about applied
-cryptography.
-
- This manual can be used in several ways. If read from the beginning
-to the end, it gives a good introduction into the library and how it can
-be used in an application. Forward references are included where
-necessary. Later on, the manual can be used as a reference manual to
-get just the information needed about any particular interface of the
-library. Experienced programmers might want to start looking at the
-examples at the end of the manual, and then only read up those parts of
-the interface which are unclear.
-
-\1f
-File: gcrypt.info, Node: Features, Next: Overview, Prev: Getting Started, Up: Introduction
-
-1.2 Features
-============
-
-Libgcrypt might have a couple of advantages over other libraries doing a
-similar job.
-
-It's Free Software
- Anybody can use, modify, and redistribute it under the terms of the
- GNU Lesser General Public License (*note Library Copying::). Note,
- that some parts (which are in general not needed by applications)
- are subject to the terms of the GNU General Public License (*note
- Copying::); please see the README file of the distribution for of
- list of these parts.
-
-It encapsulates the low level cryptography
- Libgcrypt provides a high level interface to cryptographic building
- blocks using an extensible and flexible API.
-
-\1f
-File: gcrypt.info, Node: Overview, Prev: Features, Up: Introduction
-
-1.3 Overview
-============
-
-The Libgcrypt library is fully thread-safe, where it makes sense to be
-thread-safe. Not thread-safe are some cryptographic functions that
-modify a certain context stored in handles. If the user really intents
-to use such functions from different threads on the same handle, he has
-to take care of the serialization of such functions himself. If not
-described otherwise, every function is thread-safe.
-
- Libgcrypt depends on the library 'libgpg-error', which contains some
-common code used by other GnuPG components.
-
-\1f
-File: gcrypt.info, Node: Preparation, Next: Generalities, Prev: Introduction, Up: Top
-
-2 Preparation
-*************
-
-To use Libgcrypt, you have to perform some changes to your sources and
-the build system. The necessary changes are small and explained in the
-following sections. At the end of this chapter, it is described how the
-library is initialized, and how the requirements of the library are
-verified.
-
-* Menu:
-
-* Header:: What header file you need to include.
-* Building sources:: How to build sources using the library.
-* Building sources using Automake:: How to build sources with the help of Automake.
-* Initializing the library:: How to initialize the library.
-* Multi-Threading:: How Libgcrypt can be used in a MT environment.
-* Enabling FIPS mode:: How to enable the FIPS mode.
-* Hardware features:: How to disable hardware features.
-
-\1f
-File: gcrypt.info, Node: Header, Next: Building sources, Up: Preparation
-
-2.1 Header
-==========
-
-All interfaces (data types and functions) of the library are defined in
-the header file 'gcrypt.h'. You must include this in all source files
-using the library, either directly or through some other header file,
-like this:
-
- #include <gcrypt.h>
-
- The name space of Libgcrypt is 'gcry_*' for function and type names
-and 'GCRY*' for other symbols. In addition the same name prefixes with
-one prepended underscore are reserved for internal use and should never
-be used by an application. Note that Libgcrypt uses libgpg-error, which
-uses 'gpg_*' as name space for function and type names and 'GPG_*' for
-other symbols, including all the error codes.
-
-Certain parts of gcrypt.h may be excluded by defining these macros:
-
-'GCRYPT_NO_MPI_MACROS'
- Do not define the shorthand macros 'mpi_*' for 'gcry_mpi_*'.
-
-'GCRYPT_NO_DEPRECATED'
- Do not include definitions for deprecated features. This is useful
- to make sure that no deprecated features are used.
-
-\1f
-File: gcrypt.info, Node: Building sources, Next: Building sources using Automake, Prev: Header, Up: Preparation
-
-2.2 Building sources
-====================
-
-If you want to compile a source file including the 'gcrypt.h' header
-file, you must make sure that the compiler can find it in the directory
-hierarchy. This is accomplished by adding the path to the directory in
-which the header file is located to the compilers include file search
-path (via the '-I' option).
-
- However, the path to the include file is determined at the time the
-source is configured. To solve this problem, Libgcrypt ships with a
-small helper program 'libgcrypt-config' that knows the path to the
-include file and other configuration options. The options that need to
-be added to the compiler invocation at compile time are output by the
-'--cflags' option to 'libgcrypt-config'. The following example shows
-how it can be used at the command line:
-
- gcc -c foo.c `libgcrypt-config --cflags`
-
- Adding the output of 'libgcrypt-config --cflags' to the compiler’s
-command line will ensure that the compiler can find the Libgcrypt header
-file.
-
- A similar problem occurs when linking the program with the library.
-Again, the compiler has to find the library files. For this to work,
-the path to the library files has to be added to the library search path
-(via the '-L' option). For this, the option '--libs' to
-'libgcrypt-config' can be used. For convenience, this option also
-outputs all other options that are required to link the program with the
-Libgcrypt libraries (in particular, the '-lgcrypt' option). The example
-shows how to link 'foo.o' with the Libgcrypt library to a program 'foo'.
-
- gcc -o foo foo.o `libgcrypt-config --libs`
-
- Of course you can also combine both examples to a single command by
-specifying both options to 'libgcrypt-config':
-
- gcc -o foo foo.c `libgcrypt-config --cflags --libs`
-
-\1f
-File: gcrypt.info, Node: Building sources using Automake, Next: Initializing the library, Prev: Building sources, Up: Preparation
-
-2.3 Building sources using Automake
-===================================
-
-It is much easier if you use GNU Automake instead of writing your own
-Makefiles. If you do that, you do not have to worry about finding and
-invoking the 'libgcrypt-config' script at all. Libgcrypt provides an
-extension to Automake that does all the work for you.
-
- -- Macro: AM_PATH_LIBGCRYPT ([MINIMUM-VERSION], [ACTION-IF-FOUND],
- [ACTION-IF-NOT-FOUND])
- Check whether Libgcrypt (at least version MINIMUM-VERSION, if
- given) exists on the host system. If it is found, execute
- ACTION-IF-FOUND, otherwise do ACTION-IF-NOT-FOUND, if given.
-
- Additionally, the function defines 'LIBGCRYPT_CFLAGS' to the flags
- needed for compilation of the program to find the 'gcrypt.h' header
- file, and 'LIBGCRYPT_LIBS' to the linker flags needed to link the
- program to the Libgcrypt library. If the used helper script does
- not match the target type you are building for a warning is printed
- and the string 'libgcrypt' is appended to the variable
- 'gpg_config_script_warn'.
-
- This macro searches for 'libgcrypt-config' along the PATH. If you
- are cross-compiling, it is useful to set the environment variable
- 'SYSROOT' to the top directory of your target. The macro will then
- first look for the helper program in the 'bin' directory below that
- top directory. An absolute directory name must be used for
- 'SYSROOT'. Finally, if the configure command line option
- '--with-libgcrypt-prefix' is used, only its value is used for the
- top directory below which the helper script is expected.
-
- You can use the defined Autoconf variables like this in your
-'Makefile.am':
-
- AM_CPPFLAGS = $(LIBGCRYPT_CFLAGS)
- LDADD = $(LIBGCRYPT_LIBS)
-
-\1f
-File: gcrypt.info, Node: Initializing the library, Next: Multi-Threading, Prev: Building sources using Automake, Up: Preparation
-
-2.4 Initializing the library
-============================
-
-Before the library can be used, it must initialize itself. This is
-achieved by invoking the function 'gcry_check_version' described below.
-
- Also, it is often desirable to check that the version of Libgcrypt
-used is indeed one which fits all requirements. Even with binary
-compatibility, new features may have been introduced, but due to problem
-with the dynamic linker an old version may actually be used. So you may
-want to check that the version is okay right after program startup.
-
- -- Function: const char * gcry_check_version (const char *REQ_VERSION)
-
- The function 'gcry_check_version' initializes some subsystems used
- by Libgcrypt and must be invoked before any other function in the
- library. *Note Multi-Threading::.
-
- Furthermore, this function returns the version number of the
- library. It can also verify that the version number is higher than
- a certain required version number REQ_VERSION, if this value is not
- a null pointer.
-
- Libgcrypt uses a concept known as secure memory, which is a region of
-memory set aside for storing sensitive data. Because such memory is a
-scarce resource, it needs to be setup in advanced to a fixed size.
-Further, most operating systems have special requirements on how that
-secure memory can be used. For example, it might be required to install
-an application as "setuid(root)" to allow allocating such memory.
-Libgcrypt requires a sequence of initialization steps to make sure that
-this works correctly. The following examples show the necessary steps.
-
- If you don't have a need for secure memory, for example if your
-application does not use secret keys or other confidential data or it
-runs in a controlled environment where key material floating around in
-memory is not a problem, you should initialize Libgcrypt this way:
-
- /* Version check should be the very first call because it
- makes sure that important subsystems are initialized. */
- if (!gcry_check_version (GCRYPT_VERSION))
- {
- fputs ("libgcrypt version mismatch\n", stderr);
- exit (2);
- }
-
- /* Disable secure memory. */
- gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
-
- /* ... If required, other initialization goes here. */
-
- /* Tell Libgcrypt that initialization has completed. */
- gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
-
- If you have to protect your keys or other information in memory
-against being swapped out to disk and to enable an automatic overwrite
-of used and freed memory, you need to initialize Libgcrypt this way:
-
- /* Version check should be the very first call because it
- makes sure that important subsystems are initialized. */
- if (!gcry_check_version (GCRYPT_VERSION))
- {
- fputs ("libgcrypt version mismatch\n", stderr);
- exit (2);
- }
-
- /* We don't want to see any warnings, e.g. because we have not yet
- parsed program options which might be used to suppress such
- warnings. */
- gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN);
-
- /* ... If required, other initialization goes here. Note that the
- process might still be running with increased privileges and that
- the secure memory has not been initialized. */
-
- /* Allocate a pool of 16k secure memory. This makes the secure memory
- available and also drops privileges where needed. Note that by
- using functions like gcry_xmalloc_secure and gcry_mpi_snew Libgcrypt
- may extend the secure memory pool with memory which lacks the
- property of not being swapped out to disk. */
- gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
-
- /* It is now okay to let Libgcrypt complain when there was/is
- a problem with the secure memory. */
- gcry_control (GCRYCTL_RESUME_SECMEM_WARN);
-
- /* ... If required, other initialization goes here. */
-
- /* Tell Libgcrypt that initialization has completed. */
- gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
-
- It is important that these initialization steps are not done by a
-library but by the actual application. A library using Libgcrypt might
-want to check for finished initialization using:
-
- if (!gcry_control (GCRYCTL_INITIALIZATION_FINISHED_P))
- {
- fputs ("libgcrypt has not been initialized\n", stderr);
- abort ();
- }
-
- Instead of terminating the process, the library may instead print a
-warning and try to initialize Libgcrypt itself. See also the section on
-multi-threading below for more pitfalls.
-
-\1f
-File: gcrypt.info, Node: Multi-Threading, Next: Enabling FIPS mode, Prev: Initializing the library, Up: Preparation
-
-2.5 Multi-Threading
-===================
-
-As mentioned earlier, the Libgcrypt library is thread-safe if you adhere
-to the following requirements:
-
- * If you use pthread and your applications forks and does not
- directly call exec (even calling stdio functions), all kind of
- problems may occur. Future versions of Libgcrypt will try to
- cleanup using pthread_atfork but even that may lead to problems.
- This is a common problem with almost all applications using pthread
- and fork.
-
- * The function 'gcry_check_version' must be called before any other
- function in the library. To achieve this in multi-threaded
- programs, you must synchronize the memory with respect to other
- threads that also want to use Libgcrypt. For this, it is
- sufficient to call 'gcry_check_version' before creating the other
- threads using Libgcrypt(1).
-
- * Just like the function 'gpg_strerror', the function 'gcry_strerror'
- is not thread safe. You have to use 'gpg_strerror_r' instead.
-
- ---------- Footnotes ----------
-
- (1) At least this is true for POSIX threads, as 'pthread_create' is a
-function that synchronizes memory with respects to other threads. There
-are many functions which have this property, a complete list can be
-found in POSIX, IEEE Std 1003.1-2003, Base Definitions, Issue 6, in the
-definition of the term "Memory Synchronization". For other thread
-packages, more relaxed or more strict rules may apply.
-
-\1f
-File: gcrypt.info, Node: Enabling FIPS mode, Next: Hardware features, Prev: Multi-Threading, Up: Preparation
-
-2.6 How to enable the FIPS mode
-===============================
-
-Libgcrypt may be used in a FIPS 140-2 mode. Note, that this does not
-necessary mean that Libcgrypt is an appoved FIPS 140-2 module. Check
-the NIST database at <http://csrc.nist.gov/groups/STM/cmvp/> to see what
-versions of Libgcrypt are approved.
-
- Because FIPS 140 has certain restrictions on the use of cryptography
-which are not always wanted, Libgcrypt needs to be put into FIPS mode
-explicitly. Three alternative mechanisms are provided to switch
-Libgcrypt into this mode:
-
- * If the file '/proc/sys/crypto/fips_enabled' exists and contains a
- numeric value other than '0', Libgcrypt is put into FIPS mode at
- initialization time. Obviously this works only on systems with a
- 'proc' file system (i.e. GNU/Linux).
-
- * If the file '/etc/gcrypt/fips_enabled' exists, Libgcrypt is put
- into FIPS mode at initialization time. Note that this filename is
- hardwired and does not depend on any configuration options.
-
- * If the application requests FIPS mode using the control command
- 'GCRYCTL_FORCE_FIPS_MODE'. This must be done prior to any
- initialization (i.e. before 'gcry_check_version').
-
- In addition to the standard FIPS mode, Libgcrypt may also be put into
-an Enforced FIPS mode by writing a non-zero value into the file
-'/etc/gcrypt/fips_enabled' or by using the control command
-'GCRYCTL_SET_ENFORCED_FIPS_FLAG' before any other calls to libgcrypt.
-The Enforced FIPS mode helps to detect applications which don't fulfill
-all requirements for using Libgcrypt in FIPS mode (*note FIPS Mode::).
-
- Once Libgcrypt has been put into FIPS mode, it is not possible to
-switch back to standard mode without terminating the process first. If
-the logging verbosity level of Libgcrypt has been set to at least 2, the
-state transitions and the self-tests are logged.
-
-\1f
-File: gcrypt.info, Node: Hardware features, Prev: Enabling FIPS mode, Up: Preparation
-
-2.7 How to disable hardware features
-====================================
-
-Libgcrypt makes use of certain hardware features. If the use of a
-feature is not desired it may be either be disabled by a program or
-globally using a configuration file. The currently supported features
-are
-
-'padlock-rng'
-'padlock-aes'
-'padlock-sha'
-'padlock-mmul'
-'intel-cpu'
-'intel-fast-shld'
-'intel-bmi2'
-'intel-ssse3'
-'intel-pclmul'
-'intel-aesni'
-'intel-rdrand'
-'intel-avx'
-'intel-avx2'
-'intel-rdtsc'
-'arm-neon'
-
- To disable a feature for all processes using Libgcrypt 1.6 or newer,
-create the file '/etc/gcrypt/hwf.deny' and put each feature not to be
-used on a single line. Empty lines, white space, and lines prefixed
-with a hash mark are ignored. The file should be world readable.
-
- To disable a feature specifically for a program that program must
-tell it Libgcrypt before before calling 'gcry_check_version'.
-Example:(1)
-
- gcry_control (GCRYCTL_DISABLE_HWF, "intel-rdrand", NULL);
-
-To print the list of active features you may use this command:
-
- mpicalc --print-config | grep ^hwflist: | tr : '\n' | tail -n +2
-
- ---------- Footnotes ----------
-
- (1) NB. Libgcrypt uses the RDRAND feature only as one source of
-entropy. A CPU with a broken RDRAND will thus not compromise of the
-random number generator
-
-\1f
-File: gcrypt.info, Node: Generalities, Next: Handler Functions, Prev: Preparation, Up: Top
-
-3 Generalities
-**************
-
-* Menu:
-
-* Controlling the library:: Controlling Libgcrypt's behavior.
-* Error Handling:: Error codes and such.
-
-\1f
-File: gcrypt.info, Node: Controlling the library, Next: Error Handling, Up: Generalities
-
-3.1 Controlling the library
-===========================
-
- -- Function: gcry_error_t gcry_control (enum gcry_ctl_cmds CMD, ...)
-
- This function can be used to influence the general behavior of
- Libgcrypt in several ways. Depending on CMD, more arguments can or
- have to be provided.
-
- 'GCRYCTL_ENABLE_M_GUARD; Arguments: none'
- This command enables the built-in memory guard. It must not
- be used to activate the memory guard after the memory
- management has already been used; therefore it can ONLY be
- used before 'gcry_check_version'. Note that the memory guard
- is NOT used when the user of the library has set his own
- memory management callbacks.
-
- 'GCRYCTL_ENABLE_QUICK_RANDOM; Arguments: none'
- This command inhibits the use the very secure random quality
- level ('GCRY_VERY_STRONG_RANDOM') and degrades all request
- down to 'GCRY_STRONG_RANDOM'. In general this is not
- recommended. However, for some applications the extra quality
- random Libgcrypt tries to create is not justified and this
- option may help to get better performance. Please check with
- a crypto expert whether this option can be used for your
- application.
-
- This option can only be used at initialization time.
-
- 'GCRYCTL_DUMP_RANDOM_STATS; Arguments: none'
- This command dumps random number generator related statistics
- to the library's logging stream.
-
- 'GCRYCTL_DUMP_MEMORY_STATS; Arguments: none'
- This command dumps memory management related statistics to the
- library's logging stream.
-
- 'GCRYCTL_DUMP_SECMEM_STATS; Arguments: none'
- This command dumps secure memory management related statistics
- to the library's logging stream.
-
- 'GCRYCTL_DROP_PRIVS; Arguments: none'
- This command disables the use of secure memory and drops the
- privileges of the current process. This command has not much
- use; the suggested way to disable secure memory is to use
- 'GCRYCTL_DISABLE_SECMEM' right after initialization.
-
- 'GCRYCTL_DISABLE_SECMEM; Arguments: none'
- This command disables the use of secure memory. If this
- command is used in FIPS mode, FIPS mode will be disabled and
- the function 'gcry_fips_mode_active' returns false. However,
- in Enforced FIPS mode this command has no effect at all.
-
- Many applications do not require secure memory, so they should
- disable it right away. This command should be executed right
- after 'gcry_check_version'.
-
- 'GCRYCTL_DISABLE_LOCKED_SECMEM; Arguments: none'
- This command disables the use of the mlock call for secure
- memory. Disabling the use of mlock may for example be done if
- an encrypted swap space is in use. This command should be
- executed right after 'gcry_check_version'. Note that by using
- functions like gcry_xmalloc_secure and gcry_mpi_snew Libgcrypt
- may extend the secure memory pool with memory which lacks the
- property of not being swapped out to disk (but will still be
- zeroed out on free).
-
- 'GCRYCTL_DISABLE_PRIV_DROP; Arguments: none'
- This command sets a global flag to tell the secure memory
- subsystem that it shall not drop privileges after secure
- memory has been allocated. This command is commonly used
- right after 'gcry_check_version' but may also be used right
- away at program startup. It won't have an effect after the
- secure memory pool has been initialized. WARNING: A process
- running setuid(root) is a severe security risk. Processes
- making use of Libgcrypt or other complex code should drop
- these extra privileges as soon as possible. If this command
- has been used the caller is responsible for dropping the
- privileges.
-
- 'GCRYCTL_INIT_SECMEM; Arguments: int nbytes'
- This command is used to allocate a pool of secure memory and
- thus enabling the use of secure memory. It also drops all
- extra privileges the process has (i.e. if it is run as setuid
- (root)). If the argument NBYTES is 0, secure memory will be
- disabled. The minimum amount of secure memory allocated is
- currently 16384 bytes; you may thus use a value of 1 to
- request that default size.
-
- 'GCRYCTL_TERM_SECMEM; Arguments: none'
- This command zeroises the secure memory and destroys the
- handler. The secure memory pool may not be used anymore after
- running this command. If the secure memory pool as already
- been destroyed, this command has no effect. Applications
- might want to run this command from their exit handler to make
- sure that the secure memory gets properly destroyed. This
- command is not necessarily thread-safe but that should not be
- needed in cleanup code. It may be called from a signal
- handler.
-
- 'GCRYCTL_DISABLE_SECMEM_WARN; Arguments: none'
- Disable warning messages about problems with the secure memory
- subsystem. This command should be run right after
- 'gcry_check_version'.
-
- 'GCRYCTL_SUSPEND_SECMEM_WARN; Arguments: none'
- Postpone warning messages from the secure memory subsystem.
- *Note the initialization example: sample-use-suspend-secmem,
- on how to use it.
-
- 'GCRYCTL_RESUME_SECMEM_WARN; Arguments: none'
- Resume warning messages from the secure memory subsystem.
- *Note the initialization example: sample-use-resume-secmem, on
- how to use it.
-
- 'GCRYCTL_USE_SECURE_RNDPOOL; Arguments: none'
- This command tells the PRNG to store random numbers in secure
- memory. This command should be run right after
- 'gcry_check_version' and not later than the command
- GCRYCTL_INIT_SECMEM. Note that in FIPS mode the secure memory
- is always used.
-
- 'GCRYCTL_SET_RANDOM_SEED_FILE; Arguments: const char *filename'
- This command specifies the file, which is to be used as seed
- file for the PRNG. If the seed file is registered prior to
- initialization of the PRNG, the seed file's content (if it
- exists and seems to be valid) is fed into the PRNG pool.
- After the seed file has been registered, the PRNG can be
- signalled to write out the PRNG pool's content into the seed
- file with the following command.
-
- 'GCRYCTL_UPDATE_RANDOM_SEED_FILE; Arguments: none'
- Write out the PRNG pool's content into the registered seed
- file.
-
- Multiple instances of the applications sharing the same random
- seed file can be started in parallel, in which case they will
- read out the same pool and then race for updating it (the last
- update overwrites earlier updates). They will differentiate
- only by the weak entropy that is added in read_seed_file based
- on the PID and clock, and up to 16 bytes of weak random
- non-blockingly. The consequence is that the output of these
- different instances is correlated to some extent. In a
- perfect attack scenario, the attacker can control (or at least
- guess) the PID and clock of the application, and drain the
- system's entropy pool to reduce the "up to 16 bytes" above to
- 0. Then the dependencies of the initial states of the pools
- are completely known. Note that this is not an issue if
- random of 'GCRY_VERY_STRONG_RANDOM' quality is requested as in
- this case enough extra entropy gets mixed. It is also not an
- issue when using Linux (rndlinux driver), because this one
- guarantees to read full 16 bytes from /dev/urandom and thus
- there is no way for an attacker without kernel access to
- control these 16 bytes.
-
- 'GCRYCTL_CLOSE_RANDOM_DEVICE; Arguments: none'
- Try to close the random device. If on Unix system you call
- fork(), the child process does no call exec(), and you do not
- intend to use Libgcrypt in the child, it might be useful to
- use this control code to close the inherited file descriptors
- of the random device. If Libgcrypt is later used again by the
- child, the device will be re-opened. On non-Unix systems this
- control code is ignored.
-
- 'GCRYCTL_SET_VERBOSITY; Arguments: int level'
- This command sets the verbosity of the logging. A level of 0
- disables all extra logging whereas positive numbers enable
- more verbose logging. The level may be changed at any time
- but be aware that no memory synchronization is done so the
- effect of this command might not immediately show up in other
- threads. This command may even be used prior to
- 'gcry_check_version'.
-
- 'GCRYCTL_SET_DEBUG_FLAGS; Arguments: unsigned int flags'
- Set the debug flag bits as given by the argument. Be aware
- that that no memory synchronization is done so the effect of
- this command might not immediately show up in other threads.
- The debug flags are not considered part of the API and thus
- may change without notice. As of now bit 0 enables debugging
- of cipher functions and bit 1 debugging of
- multi-precision-integers. This command may even be used prior
- to 'gcry_check_version'.
-
- 'GCRYCTL_CLEAR_DEBUG_FLAGS; Arguments: unsigned int flags'
- Set the debug flag bits as given by the argument. Be aware
- that that no memory synchronization is done so the effect of
- this command might not immediately show up in other threads.
- This command may even be used prior to 'gcry_check_version'.
-
- 'GCRYCTL_DISABLE_INTERNAL_LOCKING; Arguments: none'
- This command does nothing. It exists only for backward
- compatibility.
-
- 'GCRYCTL_ANY_INITIALIZATION_P; Arguments: none'
- This command returns true if the library has been basically
- initialized. Such a basic initialization happens implicitly
- with many commands to get certain internal subsystems running.
- The common and suggested way to do this basic initialization
- is by calling gcry_check_version.
-
- 'GCRYCTL_INITIALIZATION_FINISHED; Arguments: none'
- This command tells the library that the application has
- finished the initialization.
-
- 'GCRYCTL_INITIALIZATION_FINISHED_P; Arguments: none'
- This command returns true if the command
- GCRYCTL_INITIALIZATION_FINISHED has already been run.
-
- 'GCRYCTL_SET_THREAD_CBS; Arguments: struct ath_ops *ath_ops'
- This command is obsolete since version 1.6.
-
- 'GCRYCTL_FAST_POLL; Arguments: none'
- Run a fast random poll.
-
- 'GCRYCTL_SET_RNDEGD_SOCKET; Arguments: const char *filename'
- This command may be used to override the default name of the
- EGD socket to connect to. It may be used only during
- initialization as it is not thread safe. Changing the socket
- name again is not supported. The function may return an error
- if the given filename is too long for a local socket name.
-
- EGD is an alternative random gatherer, used only on systems
- lacking a proper random device.
-
- 'GCRYCTL_PRINT_CONFIG; Arguments: FILE *stream'
- This command dumps information pertaining to the configuration
- of the library to the given stream. If NULL is given for
- STREAM, the log system is used. This command may be used
- before the initialization has been finished but not before a
- 'gcry_check_version'. Note that the macro 'estream_t' can be
- used instead of 'gpgrt_stream_t'.
-
- 'GCRYCTL_OPERATIONAL_P; Arguments: none'
- This command returns true if the library is in an operational
- state. This information makes only sense in FIPS mode. In
- contrast to other functions, this is a pure test function and
- won't put the library into FIPS mode or change the internal
- state. This command may be used before the initialization has
- been finished but not before a 'gcry_check_version'.
-
- 'GCRYCTL_FIPS_MODE_P; Arguments: none'
- This command returns true if the library is in FIPS mode.
- Note, that this is no indication about the current state of
- the library. This command may be used before the
- initialization has been finished but not before a
- 'gcry_check_version'. An application may use this command or
- the convenience macro below to check whether FIPS mode is
- actually active.
-
- -- Function: int gcry_fips_mode_active (void)
-
- Returns true if the FIPS mode is active. Note that this
- is implemented as a macro.
-
- 'GCRYCTL_FORCE_FIPS_MODE; Arguments: none'
- Running this command puts the library into FIPS mode. If the
- library is already in FIPS mode, a self-test is triggered and
- thus the library will be put into operational state. This
- command may be used before a call to 'gcry_check_version' and
- that is actually the recommended way to let an application
- switch the library into FIPS mode. Note that Libgcrypt will
- reject an attempt to switch to fips mode during or after the
- initialization.
-
- 'GCRYCTL_SET_ENFORCED_FIPS_FLAG; Arguments: none'
- Running this command sets the internal flag that puts the
- library into the enforced FIPS mode during the FIPS mode
- initialization. This command does not affect the library if
- the library is not put into the FIPS mode and it must be used
- before any other libgcrypt library calls that initialize the
- library such as 'gcry_check_version'. Note that Libgcrypt
- will reject an attempt to switch to the enforced fips mode
- during or after the initialization.
-
- 'GCRYCTL_SET_PREFERRED_RNG_TYPE; Arguments: int'
- These are advisory commands to select a certain random number
- generator. They are only advisory because libraries may not
- know what an application actually wants or vice versa. Thus
- Libgcrypt employs a priority check to select the actually used
- RNG. If an applications selects a lower priority RNG but a
- library requests a higher priority RNG Libgcrypt will switch
- to the higher priority RNG. Applications and libraries should
- use these control codes before 'gcry_check_version'. The
- available generators are:
- 'GCRY_RNG_TYPE_STANDARD'
- A conservative standard generator based on the
- "Continuously Seeded Pseudo Random Number Generator"
- designed by Peter Gutmann.
- 'GCRY_RNG_TYPE_FIPS'
- A deterministic random number generator conforming to he
- document "NIST-Recommended Random Number Generator Based
- on ANSI X9.31 Appendix A.2.4 Using the 3-Key Triple DES
- and AES Algorithms" (2005-01-31). This implementation
- uses the AES variant.
- 'GCRY_RNG_TYPE_SYSTEM'
- A wrapper around the system's native RNG. On Unix system
- these are usually the /dev/random and /dev/urandom
- devices.
- The default is 'GCRY_RNG_TYPE_STANDARD' unless FIPS mode as
- been enabled; in which case 'GCRY_RNG_TYPE_FIPS' is used and
- locked against further changes.
-
- 'GCRYCTL_GET_CURRENT_RNG_TYPE; Arguments: int *'
- This command stores the type of the currently used RNG as an
- integer value at the provided address.
-
- 'GCRYCTL_SELFTEST; Arguments: none'
- This may be used at anytime to have the library run all
- implemented self-tests. It works in standard and in FIPS
- mode. Returns 0 on success or an error code on failure.
-
- 'GCRYCTL_DISABLE_HWF; Arguments: const char *name'
-
- Libgcrypt detects certain features of the CPU at startup time.
- For performance tests it is sometimes required not to use such
- a feature. This option may be used to disable a certain
- feature; i.e. Libgcrypt behaves as if this feature has not
- been detected. This call can be used several times to disable
- a set of features, or features may be given as a colon or
- comma delimited string. The special feature "all" can be used
- to disable all available features.
-
- Note that the detection code might be run if the feature has
- been disabled. This command must be used at initialization
- time; i.e. before calling 'gcry_check_version'.
-
- 'GCRYCTL_REINIT_SYSCALL_CLAMP; Arguments: none'
-
- Libgcrypt wraps blocking system calls with two functions calls
- ("system call clamp") to give user land threading libraries a
- hook for re-scheduling. This works by reading the system call
- clamp from Libgpg-error at initialization time. However
- sometimes Libgcrypt needs to be initialized before the user
- land threading systems and at that point the system call clamp
- has not been registered with Libgpg-error and in turn
- Libgcrypt would not use them. The control code can be used to
- tell Libgcrypt that a system call clamp has now been
- registered with Libgpg-error and advised it to read the clamp
- again. Obviously this control code may only be used before a
- second thread is started in a process.
-
-\1f
-File: gcrypt.info, Node: Error Handling, Prev: Controlling the library, Up: Generalities
-
-3.2 Error Handling
-==================
-
-Many functions in Libgcrypt can return an error if they fail. For this
-reason, the application should always catch the error condition and take
-appropriate measures, for example by releasing the resources and passing
-the error up to the caller, or by displaying a descriptive message to
-the user and cancelling the operation.
-
- Some error values do not indicate a system error or an error in the
-operation, but the result of an operation that failed properly. For
-example, if you try to decrypt a tempered message, the decryption will
-fail. Another error value actually means that the end of a data buffer
-or list has been reached. The following descriptions explain for many
-error codes what they mean usually. Some error values have specific
-meanings if returned by a certain functions. Such cases are described
-in the documentation of those functions.
-
- Libgcrypt uses the 'libgpg-error' library. This allows to share the
-error codes with other components of the GnuPG system, and to pass error
-values transparently from the crypto engine, or some helper application
-of the crypto engine, to the user. This way no information is lost. As
-a consequence, Libgcrypt does not use its own identifiers for error
-codes, but uses those provided by 'libgpg-error'. They usually start
-with 'GPG_ERR_'.
-
- However, Libgcrypt does provide aliases for the functions defined in
-libgpg-error, which might be preferred for name space consistency.
-
- Most functions in Libgcrypt return an error code in the case of
-failure. For this reason, the application should always catch the error
-condition and take appropriate measures, for example by releasing the
-resources and passing the error up to the caller, or by displaying a
-descriptive message to the user and canceling the operation.
-
- Some error values do not indicate a system error or an error in the
-operation, but the result of an operation that failed properly.
-
- GnuPG components, including Libgcrypt, use an extra library named
-libgpg-error to provide a common error handling scheme. For more
-information on libgpg-error, see the according manual.
-
-* Menu:
-
-* Error Values:: The error value and what it means.
-* Error Sources:: A list of important error sources.
-* Error Codes:: A list of important error codes.
-* Error Strings:: How to get a descriptive string from a value.
-
-\1f
-File: gcrypt.info, Node: Error Values, Next: Error Sources, Up: Error Handling
-
-3.2.1 Error Values
-------------------
-
- -- Data type: gcry_err_code_t
- The 'gcry_err_code_t' type is an alias for the 'libgpg-error' type
- 'gpg_err_code_t'. The error code indicates the type of an error,
- or the reason why an operation failed.
-
- A list of important error codes can be found in the next section.
-
- -- Data type: gcry_err_source_t
- The 'gcry_err_source_t' type is an alias for the 'libgpg-error'
- type 'gpg_err_source_t'. The error source has not a precisely
- defined meaning. Sometimes it is the place where the error
- happened, sometimes it is the place where an error was encoded into
- an error value. Usually the error source will give an indication
- to where to look for the problem. This is not always true, but it
- is attempted to achieve this goal.
-
- A list of important error sources can be found in the next section.
-
- -- Data type: gcry_error_t
- The 'gcry_error_t' type is an alias for the 'libgpg-error' type
- 'gpg_error_t'. An error value like this has always two components,
- an error code and an error source. Both together form the error
- value.
-
- Thus, the error value can not be directly compared against an error
- code, but the accessor functions described below must be used.
- However, it is guaranteed that only 0 is used to indicate success
- ('GPG_ERR_NO_ERROR'), and that in this case all other parts of the
- error value are set to 0, too.
-
- Note that in Libgcrypt, the error source is used purely for
- diagnostic purposes. Only the error code should be checked to test
- for a certain outcome of a function. The manual only documents the
- error code part of an error value. The error source is left
- unspecified and might be anything.
-
- -- Function: gcry_err_code_t gcry_err_code (gcry_error_t ERR)
- The static inline function 'gcry_err_code' returns the
- 'gcry_err_code_t' component of the error value ERR. This function
- must be used to extract the error code from an error value in order
- to compare it with the 'GPG_ERR_*' error code macros.
-
- -- Function: gcry_err_source_t gcry_err_source (gcry_error_t ERR)
- The static inline function 'gcry_err_source' returns the
- 'gcry_err_source_t' component of the error value ERR. This
- function must be used to extract the error source from an error
- value in order to compare it with the 'GPG_ERR_SOURCE_*' error
- source macros.
-
- -- Function: gcry_error_t gcry_err_make (gcry_err_source_t SOURCE,
- gcry_err_code_t CODE)
- The static inline function 'gcry_err_make' returns the error value
- consisting of the error source SOURCE and the error code CODE.
-
- This function can be used in callback functions to construct an
- error value to return it to the library.
-
- -- Function: gcry_error_t gcry_error (gcry_err_code_t CODE)
- The static inline function 'gcry_error' returns the error value
- consisting of the default error source and the error code CODE.
-
- For GCRY applications, the default error source is
- 'GPG_ERR_SOURCE_USER_1'. You can define 'GCRY_ERR_SOURCE_DEFAULT'
- before including 'gcrypt.h' to change this default.
-
- This function can be used in callback functions to construct an
- error value to return it to the library.
-
- The 'libgpg-error' library provides error codes for all system error
-numbers it knows about. If ERR is an unknown error number, the error
-code 'GPG_ERR_UNKNOWN_ERRNO' is used. The following functions can be
-used to construct error values from system errno numbers.
-
- -- Function: gcry_error_t gcry_err_make_from_errno
- (gcry_err_source_t SOURCE, int ERR)
- The function 'gcry_err_make_from_errno' is like 'gcry_err_make',
- but it takes a system error like 'errno' instead of a
- 'gcry_err_code_t' error code.
-
- -- Function: gcry_error_t gcry_error_from_errno (int ERR)
- The function 'gcry_error_from_errno' is like 'gcry_error', but it
- takes a system error like 'errno' instead of a 'gcry_err_code_t'
- error code.
-
- Sometimes you might want to map system error numbers to error codes
-directly, or map an error code representing a system error back to the
-system error number. The following functions can be used to do that.
-
- -- Function: gcry_err_code_t gcry_err_code_from_errno (int ERR)
- The function 'gcry_err_code_from_errno' returns the error code for
- the system error ERR. If ERR is not a known system error, the
- function returns 'GPG_ERR_UNKNOWN_ERRNO'.
-
- -- Function: int gcry_err_code_to_errno (gcry_err_code_t ERR)
- The function 'gcry_err_code_to_errno' returns the system error for
- the error code ERR. If ERR is not an error code representing a
- system error, or if this system error is not defined on this
- system, the function returns '0'.
-
-\1f
-File: gcrypt.info, Node: Error Sources, Next: Error Codes, Prev: Error Values, Up: Error Handling
-
-3.2.2 Error Sources
--------------------
-
-The library 'libgpg-error' defines an error source for every component
-of the GnuPG system. The error source part of an error value is not
-well defined. As such it is mainly useful to improve the diagnostic
-error message for the user.
-
- If the error code part of an error value is '0', the whole error
-value will be '0'. In this case the error source part is of course
-'GPG_ERR_SOURCE_UNKNOWN'.
-
- The list of error sources that might occur in applications using
-Libgcrypt is:
-
-'GPG_ERR_SOURCE_UNKNOWN'
- The error source is not known. The value of this error source is
- '0'.
-
-'GPG_ERR_SOURCE_GPGME'
- The error source is GPGME itself.
-
-'GPG_ERR_SOURCE_GPG'
- The error source is GnuPG, which is the crypto engine used for the
- OpenPGP protocol.
-
-'GPG_ERR_SOURCE_GPGSM'
- The error source is GPGSM, which is the crypto engine used for the
- OpenPGP protocol.
-
-'GPG_ERR_SOURCE_GCRYPT'
- The error source is 'libgcrypt', which is used by crypto engines to
- perform cryptographic operations.
-
-'GPG_ERR_SOURCE_GPGAGENT'
- The error source is 'gpg-agent', which is used by crypto engines to
- perform operations with the secret key.
-
-'GPG_ERR_SOURCE_PINENTRY'
- The error source is 'pinentry', which is used by 'gpg-agent' to
- query the passphrase to unlock a secret key.
-
-'GPG_ERR_SOURCE_SCD'
- The error source is the SmartCard Daemon, which is used by
- 'gpg-agent' to delegate operations with the secret key to a
- SmartCard.
-
-'GPG_ERR_SOURCE_KEYBOX'
- The error source is 'libkbx', a library used by the crypto engines
- to manage local keyrings.
-
-'GPG_ERR_SOURCE_USER_1'
-'GPG_ERR_SOURCE_USER_2'
-'GPG_ERR_SOURCE_USER_3'
-'GPG_ERR_SOURCE_USER_4'
- These error sources are not used by any GnuPG component and can be
- used by other software. For example, applications using Libgcrypt
- can use them to mark error values coming from callback handlers.
- Thus 'GPG_ERR_SOURCE_USER_1' is the default for errors created with
- 'gcry_error' and 'gcry_error_from_errno', unless you define
- 'GCRY_ERR_SOURCE_DEFAULT' before including 'gcrypt.h'.
-
-\1f
-File: gcrypt.info, Node: Error Codes, Next: Error Strings, Prev: Error Sources, Up: Error Handling
-
-3.2.3 Error Codes
------------------
-
-The library 'libgpg-error' defines many error values. The following
-list includes the most important error codes.
-
-'GPG_ERR_EOF'
- This value indicates the end of a list, buffer or file.
-
-'GPG_ERR_NO_ERROR'
- This value indicates success. The value of this error code is '0'.
- Also, it is guaranteed that an error value made from the error code
- '0' will be '0' itself (as a whole). This means that the error
- source information is lost for this error code, however, as this
- error code indicates that no error occurred, this is generally not
- a problem.
-
-'GPG_ERR_GENERAL'
- This value means that something went wrong, but either there is not
- enough information about the problem to return a more useful error
- value, or there is no separate error value for this type of
- problem.
-
-'GPG_ERR_ENOMEM'
- This value means that an out-of-memory condition occurred.
-
-'GPG_ERR_E...'
- System errors are mapped to GPG_ERR_EFOO where FOO is the symbol
- for the system error.
-
-'GPG_ERR_INV_VALUE'
- This value means that some user provided data was out of range.
-
-'GPG_ERR_UNUSABLE_PUBKEY'
- This value means that some recipients for a message were invalid.
-
-'GPG_ERR_UNUSABLE_SECKEY'
- This value means that some signers were invalid.
-
-'GPG_ERR_NO_DATA'
- This value means that data was expected where no data was found.
-
-'GPG_ERR_CONFLICT'
- This value means that a conflict of some sort occurred.
-
-'GPG_ERR_NOT_IMPLEMENTED'
- This value indicates that the specific function (or operation) is
- not implemented. This error should never happen. It can only
- occur if you use certain values or configuration options which do
- not work, but for which we think that they should work at some
- later time.
-
-'GPG_ERR_DECRYPT_FAILED'
- This value indicates that a decryption operation was unsuccessful.
-
-'GPG_ERR_WRONG_KEY_USAGE'
- This value indicates that a key is not used appropriately.
-
-'GPG_ERR_NO_SECKEY'
- This value indicates that no secret key for the user ID is
- available.
-
-'GPG_ERR_UNSUPPORTED_ALGORITHM'
- This value means a verification failed because the cryptographic
- algorithm is not supported by the crypto backend.
-
-'GPG_ERR_BAD_SIGNATURE'
- This value means a verification failed because the signature is
- bad.
-
-'GPG_ERR_NO_PUBKEY'
- This value means a verification failed because the public key is
- not available.
-
-'GPG_ERR_NOT_OPERATIONAL'
- This value means that the library is not yet in state which allows
- to use this function. This error code is in particular returned if
- Libgcrypt is operated in FIPS mode and the internal state of the
- library does not yet or not anymore allow the use of a service.
-
- This error code is only available with newer libgpg-error versions,
- thus you might see "invalid error code" when passing this to
- 'gpg_strerror'. The numeric value of this error code is 176.
-
-'GPG_ERR_USER_1'
-'GPG_ERR_USER_2'
-'...'
-'GPG_ERR_USER_16'
- These error codes are not used by any GnuPG component and can be
- freely used by other software. Applications using Libgcrypt might
- use them to mark specific errors returned by callback handlers if
- no suitable error codes (including the system errors) for these
- errors exist already.
-
-\1f
-File: gcrypt.info, Node: Error Strings, Prev: Error Codes, Up: Error Handling
-
-3.2.4 Error Strings
--------------------
-
- -- Function: const char * gcry_strerror (gcry_error_t ERR)
- The function 'gcry_strerror' returns a pointer to a statically
- allocated string containing a description of the error code
- contained in the error value ERR. This string can be used to
- output a diagnostic message to the user.
-
- -- Function: const char * gcry_strsource (gcry_error_t ERR)
- The function 'gcry_strsource' returns a pointer to a statically
- allocated string containing a description of the error source
- contained in the error value ERR. This string can be used to
- output a diagnostic message to the user.
-
- The following example illustrates the use of the functions described
-above:
-
- {
- gcry_cipher_hd_t handle;
- gcry_error_t err = 0;
-
- err = gcry_cipher_open (&handle, GCRY_CIPHER_AES,
- GCRY_CIPHER_MODE_CBC, 0);
- if (err)
- {
- fprintf (stderr, "Failure: %s/%s\n",
- gcry_strsource (err),
- gcry_strerror (err));
- }
- }
-
-\1f
-File: gcrypt.info, Node: Handler Functions, Next: Symmetric cryptography, Prev: Generalities, Up: Top
-
-4 Handler Functions
-*******************
-
-Libgcrypt makes it possible to install so called 'handler functions',
-which get called by Libgcrypt in case of certain events.
-
-* Menu:
-
-* Progress handler:: Using a progress handler function.
-* Allocation handler:: Using special memory allocation functions.
-* Error handler:: Using error handler functions.
-* Logging handler:: Using a special logging function.
-
-\1f
-File: gcrypt.info, Node: Progress handler, Next: Allocation handler, Up: Handler Functions
-
-4.1 Progress handler
-====================
-
-It is often useful to retrieve some feedback while long running
-operations are performed.
-
- -- Data type: gcry_handler_progress_t
- Progress handler functions have to be of the type
- 'gcry_handler_progress_t', which is defined as:
-
- 'void (*gcry_handler_progress_t) (void *, const char *, int, int,
- int)'
-
- The following function may be used to register a handler function for
-this purpose.
-
- -- Function: void gcry_set_progress_handler (gcry_handler_progress_t
- CB, void *CB_DATA)
-
- This function installs CB as the 'Progress handler' function. It
- may be used only during initialization. CB must be defined as
- follows:
-
- void
- my_progress_handler (void *CB_DATA, const char *WHAT,
- int PRINTCHAR, int CURRENT, int TOTAL)
- {
- /* Do something. */
- }
-
- A description of the arguments of the progress handler function
- follows.
-
- CB_DATA
- The argument provided in the call to
- 'gcry_set_progress_handler'.
- WHAT
- A string identifying the type of the progress output. The
- following values for WHAT are defined:
-
- 'need_entropy'
- Not enough entropy is available. TOTAL holds the number
- of required bytes.
-
- 'wait_dev_random'
- Waiting to re-open a random device. TOTAL gives the
- number of seconds until the next try.
-
- 'primegen'
- Values for PRINTCHAR:
- '\n'
- Prime generated.
- '!'
- Need to refresh the pool of prime numbers.
- '<, >'
- Number of bits adjusted.
- '^'
- Searching for a generator.
- '.'
- Fermat test on 10 candidates failed.
- ':'
- Restart with a new random value.
- '+'
- Rabin Miller test passed.
-
-\1f
-File: gcrypt.info, Node: Allocation handler, Next: Error handler, Prev: Progress handler, Up: Handler Functions
-
-4.2 Allocation handler
-======================
-
-It is possible to make Libgcrypt use special memory allocation functions
-instead of the built-in ones.
-
- Memory allocation functions are of the following types:
- -- Data type: gcry_handler_alloc_t
- This type is defined as: 'void *(*gcry_handler_alloc_t) (size_t
- n)'.
- -- Data type: gcry_handler_secure_check_t
- This type is defined as: 'int *(*gcry_handler_secure_check_t)
- (const void *)'.
- -- Data type: gcry_handler_realloc_t
- This type is defined as: 'void *(*gcry_handler_realloc_t) (void *p,
- size_t n)'.
- -- Data type: gcry_handler_free_t
- This type is defined as: 'void *(*gcry_handler_free_t) (void *)'.
-
- Special memory allocation functions can be installed with the
-following function:
-
- -- Function: void gcry_set_allocation_handler (gcry_handler_alloc_t
- FUNC_ALLOC, gcry_handler_alloc_t FUNC_ALLOC_SECURE,
- gcry_handler_secure_check_t FUNC_SECURE_CHECK,
- gcry_handler_realloc_t FUNC_REALLOC, gcry_handler_free_t
- FUNC_FREE)
- Install the provided functions and use them instead of the built-in
- functions for doing memory allocation. Using this function is in
- general not recommended because the standard Libgcrypt allocation
- functions are guaranteed to zeroize memory if needed.
-
- This function may be used only during initialization and may not be
- used in fips mode.
-
-\1f
-File: gcrypt.info, Node: Error handler, Next: Logging handler, Prev: Allocation handler, Up: Handler Functions
-
-4.3 Error handler
-=================
-
-The following functions may be used to register handler functions that
-are called by Libgcrypt in case certain error conditions occur. They
-may and should be registered prior to calling 'gcry_check_version'.
-
- -- Data type: gcry_handler_no_mem_t
- This type is defined as: 'int (*gcry_handler_no_mem_t) (void *,
- size_t, unsigned int)'
- -- Function: void gcry_set_outofcore_handler (gcry_handler_no_mem_t
- FUNC_NO_MEM, void *CB_DATA)
- This function registers FUNC_NO_MEM as 'out-of-core handler', which
- means that it will be called in the case of not having enough
- memory available. The handler is called with 3 arguments: The
- first one is the pointer CB_DATA as set with this function, the
- second is the requested memory size and the last being a flag. If
- bit 0 of the flag is set, secure memory has been requested. The
- handler should either return true to indicate that Libgcrypt should
- try again allocating memory or return false to let Libgcrypt use
- its default fatal error handler.
-
- -- Data type: gcry_handler_error_t
- This type is defined as: 'void (*gcry_handler_error_t) (void *,
- int, const char *)'
-
- -- Function: void gcry_set_fatalerror_handler (gcry_handler_error_t
- FUNC_ERROR, void *CB_DATA)
- This function registers FUNC_ERROR as 'error handler', which means
- that it will be called in error conditions.
-
-\1f
-File: gcrypt.info, Node: Logging handler, Prev: Error handler, Up: Handler Functions
-
-4.4 Logging handler
-===================
-
- -- Data type: gcry_handler_log_t
- This type is defined as: 'void (*gcry_handler_log_t) (void *, int,
- const char *, va_list)'
-
- -- Function: void gcry_set_log_handler (gcry_handler_log_t FUNC_LOG,
- void *CB_DATA)
- This function registers FUNC_LOG as 'logging handler', which means
- that it will be called in case Libgcrypt wants to log a message.
- This function may and should be used prior to calling
- 'gcry_check_version'.
-
-\1f
-File: gcrypt.info, Node: Symmetric cryptography, Next: Public Key cryptography, Prev: Handler Functions, Up: Top
-
-5 Symmetric cryptography
-************************
-
-The cipher functions are used for symmetrical cryptography, i.e.
-cryptography using a shared key. The programming model follows an
-open/process/close paradigm and is in that similar to other building
-blocks provided by Libgcrypt.
-
-* Menu:
-
-* Available ciphers:: List of ciphers supported by the library.
-* Available cipher modes:: List of cipher modes supported by the library.
-* Working with cipher handles:: How to perform operations related to cipher handles.
-* General cipher functions:: General cipher functions independent of cipher handles.
-
-\1f
-File: gcrypt.info, Node: Available ciphers, Next: Available cipher modes, Up: Symmetric cryptography
-
-5.1 Available ciphers
-=====================
-
-'GCRY_CIPHER_NONE'
- This is not a real algorithm but used by some functions as error
- return. The value always evaluates to false.
-
-'GCRY_CIPHER_IDEA'
- This is the IDEA algorithm.
-
-'GCRY_CIPHER_3DES'
- Triple-DES with 3 Keys as EDE. The key size of this algorithm is
- 168 but you have to pass 192 bits because the most significant bits
- of each byte are ignored.
-
-'GCRY_CIPHER_CAST5'
- CAST128-5 block cipher algorithm. The key size is 128 bits.
-
-'GCRY_CIPHER_BLOWFISH'
- The blowfish algorithm. The current implementation allows only for
- a key size of 128 bits.
-
-'GCRY_CIPHER_SAFER_SK128'
- Reserved and not currently implemented.
-
-'GCRY_CIPHER_DES_SK'
- Reserved and not currently implemented.
-
-'GCRY_CIPHER_AES'
-'GCRY_CIPHER_AES128'
-'GCRY_CIPHER_RIJNDAEL'
-'GCRY_CIPHER_RIJNDAEL128'
- AES (Rijndael) with a 128 bit key.
-
-'GCRY_CIPHER_AES192'
-'GCRY_CIPHER_RIJNDAEL192'
- AES (Rijndael) with a 192 bit key.
-
-'GCRY_CIPHER_AES256'
-'GCRY_CIPHER_RIJNDAEL256'
- AES (Rijndael) with a 256 bit key.
-
-'GCRY_CIPHER_TWOFISH'
- The Twofish algorithm with a 256 bit key.
-
-'GCRY_CIPHER_TWOFISH128'
- The Twofish algorithm with a 128 bit key.
-
-'GCRY_CIPHER_ARCFOUR'
- An algorithm which is 100% compatible with RSA Inc.'s RC4
- algorithm. Note that this is a stream cipher and must be used very
- carefully to avoid a couple of weaknesses.
-
-'GCRY_CIPHER_DES'
- Standard DES with a 56 bit key. You need to pass 64 bit but the
- high bits of each byte are ignored. Note, that this is a weak
- algorithm which can be broken in reasonable time using a brute
- force approach.
-
-'GCRY_CIPHER_SERPENT128'
-'GCRY_CIPHER_SERPENT192'
-'GCRY_CIPHER_SERPENT256'
- The Serpent cipher from the AES contest.
-
-'GCRY_CIPHER_RFC2268_40'
-'GCRY_CIPHER_RFC2268_128'
- Ron's Cipher 2 in the 40 and 128 bit variants.
-
-'GCRY_CIPHER_SEED'
- A 128 bit cipher as described by RFC4269.
-
-'GCRY_CIPHER_CAMELLIA128'
-'GCRY_CIPHER_CAMELLIA192'
-'GCRY_CIPHER_CAMELLIA256'
- The Camellia cipher by NTT. See
- <http://info.isl.ntt.co.jp/crypt/eng/camellia/specifications.html>.
-
-'GCRY_CIPHER_SALSA20'
- This is the Salsa20 stream cipher.
-
-'GCRY_CIPHER_SALSA20R12'
- This is the Salsa20/12 - reduced round version of Salsa20 stream
- cipher.
-
-'GCRY_CIPHER_GOST28147'
- The GOST 28147-89 cipher, defined in the respective GOST standard.
- Translation of this GOST into English is provided in the RFC-5830.
-
-'GCRY_CIPHER_CHACHA20'
- This is the ChaCha20 stream cipher.
-
-\1f
-File: gcrypt.info, Node: Available cipher modes, Next: Working with cipher handles, Prev: Available ciphers, Up: Symmetric cryptography
-
-5.2 Available cipher modes
-==========================
-
-'GCRY_CIPHER_MODE_NONE'
- No mode specified. This should not be used. The only exception is
- that if Libgcrypt is not used in FIPS mode and if any debug flag
- has been set, this mode may be used to bypass the actual
- encryption.
-
-'GCRY_CIPHER_MODE_ECB'
- Electronic Codebook mode.
-
-'GCRY_CIPHER_MODE_CFB'
-'GCRY_CIPHER_MODE_CFB8'
- Cipher Feedback mode. For GCRY_CIPHER_MODE_CFB the shift size
- equals the block size of the cipher (e.g. for AES it is CFB-128).
- For GCRY_CIPHER_MODE_CFB8 the shift size is 8 bit but that variant
- is not yet available.
-
-'GCRY_CIPHER_MODE_CBC'
- Cipher Block Chaining mode.
-
-'GCRY_CIPHER_MODE_STREAM'
- Stream mode, only to be used with stream cipher algorithms.
-
-'GCRY_CIPHER_MODE_OFB'
- Output Feedback mode.
-
-'GCRY_CIPHER_MODE_CTR'
- Counter mode.
-
-'GCRY_CIPHER_MODE_AESWRAP'
- This mode is used to implement the AES-Wrap algorithm according to
- RFC-3394. It may be used with any 128 bit block length algorithm,
- however the specs require one of the 3 AES algorithms. These
- special conditions apply: If 'gcry_cipher_setiv' has not been used
- the standard IV is used; if it has been used the lower 64 bit of
- the IV are used as the Alternative Initial Value. On encryption
- the provided output buffer must be 64 bit (8 byte) larger than the
- input buffer; in-place encryption is still allowed. On decryption
- the output buffer may be specified 64 bit (8 byte) shorter than
- then input buffer. As per specs the input length must be at least
- 128 bits and the length must be a multiple of 64 bits.
-
-'GCRY_CIPHER_MODE_CCM'
- Counter with CBC-MAC mode is an Authenticated Encryption with
- Associated Data (AEAD) block cipher mode, which is specified in
- 'NIST Special Publication 800-38C' and RFC 3610.
-
-'GCRY_CIPHER_MODE_GCM'
- Galois/Counter Mode (GCM) is an Authenticated Encryption with
- Associated Data (AEAD) block cipher mode, which is specified in
- 'NIST Special Publication 800-38D'.
-
-'GCRY_CIPHER_MODE_POLY1305'
- This mode implements the Poly1305 Authenticated Encryption with
- Associated Data (AEAD) mode according to RFC-7539. This mode can
- be used with ChaCha20 stream cipher.
-
-'GCRY_CIPHER_MODE_OCB'
- OCB is an Authenticated Encryption with Associated Data (AEAD)
- block cipher mode, which is specified in RFC-7253. Supported tag
- lengths are 128, 96, and 64 bit with the default being 128 bit. To
- switch to a different tag length 'gcry_cipher_ctl' using the
- command 'GCRYCTL_SET_TAGLEN' and the address of an 'int' variable
- set to 12 (for 96 bit) or 8 (for 64 bit) provided for the 'buffer'
- argument and 'sizeof(int)' for 'buflen'.
-
- Note that the use of 'gcry_cipher_final' is required.
-
-'GCRY_CIPHER_MODE_XTS'
- XEX-based tweaked-codebook mode with ciphertext stealing (XTS) mode
- is used to implement the AES-XTS as specified in IEEE 1619 Standard
- Architecture for Encrypted Shared Storage Media and NIST SP800-38E.
-
- The XTS mode requires doubling key-length, for example, using
- 512-bit key with AES-256 ('GCRY_CIPHER_AES256'). The 128-bit tweak
- value is feed to XTS mode as little-endian byte array using
- 'gcry_cipher_setiv' function. When encrypting or decrypting,
- full-sized data unit buffers needs to be passed to
- 'gcry_cipher_encrypt' or 'gcry_cipher_decrypt'. The tweak value is
- automatically incremented after each call of 'gcry_cipher_encrypt'
- and 'gcry_cipher_decrypt'. Auto-increment allows avoiding need of
- setting IV between processing of sequential data units.
-
-\1f
-File: gcrypt.info, Node: Working with cipher handles, Next: General cipher functions, Prev: Available cipher modes, Up: Symmetric cryptography
-
-5.3 Working with cipher handles
-===============================
-
-To use a cipher algorithm, you must first allocate an according handle.
-This is to be done using the open function:
-
- -- Function: gcry_error_t gcry_cipher_open (gcry_cipher_hd_t *HD, int
- ALGO, int MODE, unsigned int FLAGS)
-
- This function creates the context handle required for most of the
- other cipher functions and returns a handle to it in 'hd'. In case
- of an error, an according error code is returned.
-
- The ID of algorithm to use must be specified via ALGO. See *Note
- Available ciphers::, for a list of supported ciphers and the
- according constants.
-
- Besides using the constants directly, the function
- 'gcry_cipher_map_name' may be used to convert the textual name of
- an algorithm into the according numeric ID.
-
- The cipher mode to use must be specified via MODE. See *Note
- Available cipher modes::, for a list of supported cipher modes and
- the according constants. Note that some modes are incompatible
- with some algorithms - in particular, stream mode
- ('GCRY_CIPHER_MODE_STREAM') only works with stream ciphers.
- Poly1305 AEAD mode ('GCRY_CIPHER_MODE_POLY1305') only works with
- ChaCha20 stream cipher. The block cipher modes
- ('GCRY_CIPHER_MODE_ECB', 'GCRY_CIPHER_MODE_CBC',
- 'GCRY_CIPHER_MODE_CFB', 'GCRY_CIPHER_MODE_OFB' and
- 'GCRY_CIPHER_MODE_CTR') will work with any block cipher algorithm.
- GCM mode ('GCRY_CIPHER_MODE_CCM'), CCM mode
- ('GCRY_CIPHER_MODE_GCM'), OCB mode ('GCRY_CIPHER_MODE_OCB'), and
- XTS mode ('GCRY_CIPHER_MODE_XTS') will only work with block cipher
- algorithms which have the block size of 16 bytes.
-
- The third argument FLAGS can either be passed as '0' or as the
- bit-wise OR of the following constants.
-
- 'GCRY_CIPHER_SECURE'
- Make sure that all operations are allocated in secure memory.
- This is useful when the key material is highly confidential.
- 'GCRY_CIPHER_ENABLE_SYNC'
- This flag enables the CFB sync mode, which is a special
- feature of Libgcrypt's CFB mode implementation to allow for
- OpenPGP's CFB variant. See 'gcry_cipher_sync'.
- 'GCRY_CIPHER_CBC_CTS'
- Enable cipher text stealing (CTS) for the CBC mode. Cannot be
- used simultaneous as GCRY_CIPHER_CBC_MAC. CTS mode makes it
- possible to transform data of almost arbitrary size (only
- limitation is that it must be greater than the algorithm's
- block size).
- 'GCRY_CIPHER_CBC_MAC'
- Compute CBC-MAC keyed checksums. This is the same as CBC
- mode, but only output the last block. Cannot be used
- simultaneous as GCRY_CIPHER_CBC_CTS.
-
- Use the following function to release an existing handle:
-
- -- Function: void gcry_cipher_close (gcry_cipher_hd_t H)
-
- This function releases the context created by 'gcry_cipher_open'.
- It also zeroises all sensitive information associated with this
- cipher handle.
-
- In order to use a handle for performing cryptographic operations, a
-'key' has to be set first:
-
- -- Function: gcry_error_t gcry_cipher_setkey (gcry_cipher_hd_t H, const
- void *K, size_t L)
-
- Set the key K used for encryption or decryption in the context
- denoted by the handle H. The length L (in bytes) of the key K must
- match the required length of the algorithm set for this context or
- be in the allowed range for algorithms with variable key size. The
- function checks this and returns an error if there is a problem. A
- caller should always check for an error.
-
- Most crypto modes requires an initialization vector (IV), which
-usually is a non-secret random string acting as a kind of salt value.
-The CTR mode requires a counter, which is also similar to a salt value.
-To set the IV or CTR, use these functions:
-
- -- Function: gcry_error_t gcry_cipher_setiv (gcry_cipher_hd_t H, const
- void *K, size_t L)
-
- Set the initialization vector used for encryption or decryption.
- The vector is passed as the buffer K of length L bytes and copied
- to internal data structures. The function checks that the IV
- matches the requirement of the selected algorithm and mode.
-
- This function is also used by AEAD modes and with Salsa20 and
- ChaCha20 stream ciphers to set or update the required nonce. In
- these cases it needs to be called after setting the key.
-
- -- Function: gcry_error_t gcry_cipher_setctr (gcry_cipher_hd_t H, const
- void *C, size_t L)
-
- Set the counter vector used for encryption or decryption. The
- counter is passed as the buffer C of length L bytes and copied to
- internal data structures. The function checks that the counter
- matches the requirement of the selected algorithm (i.e., it must be
- the same size as the block size).
-
- -- Function: gcry_error_t gcry_cipher_reset (gcry_cipher_hd_t H)
-
- Set the given handle's context back to the state it had after the
- last call to gcry_cipher_setkey and clear the initialization
- vector.
-
- Note that gcry_cipher_reset is implemented as a macro.
-
- Authenticated Encryption with Associated Data (AEAD) block cipher
-modes require the handling of the authentication tag and the additional
-authenticated data, which can be done by using the following functions:
-
- -- Function: gcry_error_t gcry_cipher_authenticate (gcry_cipher_hd_t H,
- const void *ABUF, size_t ABUFLEN)
-
- Process the buffer ABUF of length ABUFLEN as the additional
- authenticated data (AAD) for AEAD cipher modes.
-
- -- Function: gcry_error_t gcry_cipher_gettag (gcry_cipher_hd_t H,
- void *TAG, size_t TAGLEN)
-
- This function is used to read the authentication tag after
- encryption. The function finalizes and outputs the authentication
- tag to the buffer TAG of length TAGLEN bytes.
-
- Depending on the used mode certain restrictions for TAGLEN are
- enforced: For GCM TAGLEN must be at least 16 or one of the allowed
- truncated lengths (4, 8, 12, 13, 14, or 15).
-
- -- Function: gcry_error_t gcry_cipher_checktag (gcry_cipher_hd_t H,
- const void *TAG, size_t TAGLEN)
-
- Check the authentication tag after decryption. The authentication
- tag is passed as the buffer TAG of length TAGLEN bytes and compared
- to internal authentication tag computed during decryption. Error
- code 'GPG_ERR_CHECKSUM' is returned if the authentication tag in
- the buffer TAG does not match the authentication tag calculated
- during decryption.
-
- Depending on the used mode certain restrictions for TAGLEN are
- enforced: For GCM TAGLEN must either be 16 or one of the allowed
- truncated lengths (4, 8, 12, 13, 14, or 15).
-
- The actual encryption and decryption is done by using one of the
-following functions. They may be used as often as required to process
-all the data.
-
- -- Function: gcry_error_t gcry_cipher_encrypt (gcry_cipher_hd_t H,
- unsigned char *out, size_t OUTSIZE, const unsigned char *IN,
- size_t INLEN)
-
- 'gcry_cipher_encrypt' is used to encrypt the data. This function
- can either work in place or with two buffers. It uses the cipher
- context already setup and described by the handle H. There are 2
- ways to use the function: If IN is passed as 'NULL' and INLEN is
- '0', in-place encryption of the data in OUT of length OUTSIZE takes
- place. With IN being not 'NULL', INLEN bytes are encrypted to the
- buffer OUT which must have at least a size of INLEN. OUTSIZE must
- be set to the allocated size of OUT, so that the function can check
- that there is sufficient space. Note that overlapping buffers are
- not allowed.
-
- Depending on the selected algorithms and encryption mode, the
- length of the buffers must be a multiple of the block size.
-
- Some encryption modes require that 'gcry_cipher_final' is used
- before the final data chunk is passed to this function.
-
- The function returns '0' on success or an error code.
-
- -- Function: gcry_error_t gcry_cipher_decrypt (gcry_cipher_hd_t H,
- unsigned char *out, size_t OUTSIZE, const unsigned char *IN,
- size_t INLEN)
-
- 'gcry_cipher_decrypt' is used to decrypt the data. This function
- can either work in place or with two buffers. It uses the cipher
- context already setup and described by the handle H. There are 2
- ways to use the function: If IN is passed as 'NULL' and INLEN is
- '0', in-place decryption of the data in OUT or length OUTSIZE takes
- place. With IN being not 'NULL', INLEN bytes are decrypted to the
- buffer OUT which must have at least a size of INLEN. OUTSIZE must
- be set to the allocated size of OUT, so that the function can check
- that there is sufficient space. Note that overlapping buffers are
- not allowed.
-
- Depending on the selected algorithms and encryption mode, the
- length of the buffers must be a multiple of the block size.
-
- Some encryption modes require that 'gcry_cipher_final' is used
- before the final data chunk is passed to this function.
-
- The function returns '0' on success or an error code.
-
- The OCB mode features integrated padding and must thus be told about
-the end of the input data. This is done with:
-
- -- Function: gcry_error_t gcry_cipher_final (gcry_cipher_hd_t H)
-
- Set a flag in the context to tell the encrypt and decrypt functions
- that their next call will provide the last chunk of data. Only the
- first call to this function has an effect and only for modes which
- support it. Checking the error is in general not necessary. This
- is implemented as a macro.
-
- OpenPGP (as defined in RFC-4880) requires a special sync operation in
-some places. The following function is used for this:
-
- -- Function: gcry_error_t gcry_cipher_sync (gcry_cipher_hd_t H)
-
- Perform the OpenPGP sync operation on context H. Note that this is
- a no-op unless the context was created with the flag
- 'GCRY_CIPHER_ENABLE_SYNC'
-
- Some of the described functions are implemented as macros utilizing a
-catch-all control function. This control function is rarely used
-directly but there is nothing which would inhibit it:
-
- -- Function: gcry_error_t gcry_cipher_ctl (gcry_cipher_hd_t H, int CMD,
- void *BUFFER, size_t BUFLEN)
-
- 'gcry_cipher_ctl' controls various aspects of the cipher module and
- specific cipher contexts. Usually some more specialized functions
- or macros are used for this purpose. The semantics of the function
- and its parameters depends on the the command CMD and the passed
- context handle H. Please see the comments in the source code
- ('src/global.c') for details.
-
- -- Function: gcry_error_t gcry_cipher_info (gcry_cipher_hd_t H, int
- WHAT, void *BUFFER, size_t *NBYTES)
-
- 'gcry_cipher_info' is used to retrieve various information about a
- cipher context or the cipher module in general.
-
- 'GCRYCTL_GET_TAGLEN:'
- Return the length of the tag for an AE algorithm mode. An
- error is returned for modes which do not support a tag.
- BUFFER must be given as NULL. On success the result is stored
- NBYTES. The taglen is returned in bytes.
-
-\1f
-File: gcrypt.info, Node: General cipher functions, Prev: Working with cipher handles, Up: Symmetric cryptography
-
-5.4 General cipher functions
-============================
-
-To work with the algorithms, several functions are available to map
-algorithm names to the internal identifiers, as well as ways to retrieve
-information about an algorithm or the current cipher context.
-
- -- Function: gcry_error_t gcry_cipher_algo_info (int ALGO, int WHAT,
- void *BUFFER, size_t *NBYTES)
-
- This function is used to retrieve information on a specific
- algorithm. You pass the cipher algorithm ID as ALGO and the type
- of information requested as WHAT. The result is either returned as
- the return code of the function or copied to the provided BUFFER
- whose allocated length must be available in an integer variable
- with the address passed in NBYTES. This variable will also receive
- the actual used length of the buffer.
-
- Here is a list of supported codes for WHAT:
-
- 'GCRYCTL_GET_KEYLEN:'
- Return the length of the key. If the algorithm supports
- multiple key lengths, the maximum supported value is returned.
- The length is returned as number of octets (bytes) and not as
- number of bits in NBYTES; BUFFER must be zero. Note that it
- is usually better to use the convenience function
- 'gcry_cipher_get_algo_keylen'.
-
- 'GCRYCTL_GET_BLKLEN:'
- Return the block length of the algorithm. The length is
- returned as a number of octets in NBYTES; BUFFER must be zero.
- Note that it is usually better to use the convenience function
- 'gcry_cipher_get_algo_blklen'.
-
- 'GCRYCTL_TEST_ALGO:'
- Returns '0' when the specified algorithm is available for use.
- BUFFER and NBYTES must be zero.
-
- -- Function: size_t gcry_cipher_get_algo_keylen (ALGO)
-
- This function returns length of the key for algorithm ALGO. If the
- algorithm supports multiple key lengths, the maximum supported key
- length is returned. On error '0' is returned. The key length is
- returned as number of octets.
-
- This is a convenience functions which should be preferred over
- 'gcry_cipher_algo_info' because it allows for proper type checking.
-
- -- Function: size_t gcry_cipher_get_algo_blklen (int ALGO)
-
- This functions returns the block-length of the algorithm ALGO
- counted in octets. On error '0' is returned.
-
- This is a convenience functions which should be preferred over
- 'gcry_cipher_algo_info' because it allows for proper type checking.
-
- -- Function: const char * gcry_cipher_algo_name (int ALGO)
-
- 'gcry_cipher_algo_name' returns a string with the name of the
- cipher algorithm ALGO. If the algorithm is not known or another
- error occurred, the string '"?"' is returned. This function should
- not be used to test for the availability of an algorithm.
-
- -- Function: int gcry_cipher_map_name (const char *NAME)
-
- 'gcry_cipher_map_name' returns the algorithm identifier for the
- cipher algorithm described by the string NAME. If this algorithm
- is not available '0' is returned.
-
- -- Function: int gcry_cipher_mode_from_oid (const char *STRING)
-
- Return the cipher mode associated with an ASN.1 object identifier.
- The object identifier is expected to be in the IETF-style dotted
- decimal notation. The function returns '0' for an unknown object
- identifier or when no mode is associated with it.
-
-\1f
-File: gcrypt.info, Node: Public Key cryptography, Next: Hashing, Prev: Symmetric cryptography, Up: Top
-
-6 Public Key cryptography
-*************************
-
-Public key cryptography, also known as asymmetric cryptography, is an
-easy way for key management and to provide digital signatures.
-Libgcrypt provides two completely different interfaces to public key
-cryptography, this chapter explains the one based on S-expressions.
-
-* Menu:
-
-* Available algorithms:: Algorithms supported by the library.
-* Used S-expressions:: Introduction into the used S-expression.
-* Cryptographic Functions:: Functions for performing the cryptographic actions.
-* General public-key related Functions:: General functions, not implementing any cryptography.
-
-\1f
-File: gcrypt.info, Node: Available algorithms, Next: Used S-expressions, Up: Public Key cryptography
-
-6.1 Available algorithms
-========================
-
-Libgcrypt supports the RSA (Rivest-Shamir-Adleman) algorithms as well as
-DSA (Digital Signature Algorithm) and Elgamal. The versatile interface
-allows to add more algorithms in the future.
-
-\1f
-File: gcrypt.info, Node: Used S-expressions, Next: Cryptographic Functions, Prev: Available algorithms, Up: Public Key cryptography
-
-6.2 Used S-expressions
-======================
-
-Libgcrypt's API for asymmetric cryptography is based on data structures
-called S-expressions (see
-<http://people.csail.mit.edu/rivest/sexp.html>) and does not work with
-contexts as most of the other building blocks of Libgcrypt do.
-
-The following information are stored in S-expressions:
-
- * keys
-
- * plain text data
-
- * encrypted data
-
- * signatures
-
-To describe how Libgcrypt expect keys, we use examples. Note that words
-in uppercase indicate parameters whereas lowercase words are literals.
-
- Note that all MPI (multi-precision-integers) values are expected to
-be in 'GCRYMPI_FMT_USG' format. An easy way to create S-expressions is
-by using 'gcry_sexp_build' which allows to pass a string with
-printf-like escapes to insert MPI values.
-
-* Menu:
-
-* RSA key parameters:: Parameters used with an RSA key.
-* DSA key parameters:: Parameters used with a DSA key.
-* ECC key parameters:: Parameters used with ECC keys.
-
-\1f
-File: gcrypt.info, Node: RSA key parameters, Next: DSA key parameters, Up: Used S-expressions
-
-6.2.1 RSA key parameters
-------------------------
-
-An RSA private key is described by this S-expression:
-
- (private-key
- (rsa
- (n N-MPI)
- (e E-MPI)
- (d D-MPI)
- (p P-MPI)
- (q Q-MPI)
- (u U-MPI)))
-
-An RSA public key is described by this S-expression:
-
- (public-key
- (rsa
- (n N-MPI)
- (e E-MPI)))
-
-N-MPI
- RSA public modulus n.
-E-MPI
- RSA public exponent e.
-D-MPI
- RSA secret exponent d = e^{-1} \bmod (p-1)(q-1).
-P-MPI
- RSA secret prime p.
-Q-MPI
- RSA secret prime q with p < q.
-U-MPI
- Multiplicative inverse u = p^{-1} \bmod q.
-
- For signing and decryption the parameters (p, q, u) are optional but
-greatly improve the performance. Either all of these optional
-parameters must be given or none of them. They are mandatory for
-gcry_pk_testkey.
-
- Note that OpenSSL uses slighly different parameters: q < p and u =
-q^{-1} \bmod p. To use these parameters you will need to swap the
-values and recompute u. Here is example code to do this:
-
- if (gcry_mpi_cmp (p, q) > 0)
- {
- gcry_mpi_swap (p, q);
- gcry_mpi_invm (u, p, q);
- }
-
-\1f
-File: gcrypt.info, Node: DSA key parameters, Next: ECC key parameters, Prev: RSA key parameters, Up: Used S-expressions
-
-6.2.2 DSA key parameters
-------------------------
-
-A DSA private key is described by this S-expression:
-
- (private-key
- (dsa
- (p P-MPI)
- (q Q-MPI)
- (g G-MPI)
- (y Y-MPI)
- (x X-MPI)))
-
-P-MPI
- DSA prime p.
-Q-MPI
- DSA group order q (which is a prime divisor of p-1).
-G-MPI
- DSA group generator g.
-Y-MPI
- DSA public key value y = g^x \bmod p.
-X-MPI
- DSA secret exponent x.
-
- The public key is similar with "private-key" replaced by "public-key"
-and no X-MPI.
-
-\1f
-File: gcrypt.info, Node: ECC key parameters, Prev: DSA key parameters, Up: Used S-expressions
-
-6.2.3 ECC key parameters
-------------------------
-
-An ECC private key is described by this S-expression:
-
- (private-key
- (ecc
- (p P-MPI)
- (a A-MPI)
- (b B-MPI)
- (g G-POINT)
- (n N-MPI)
- (q Q-POINT)
- (d D-MPI)))
-
-P-MPI
- Prime specifying the field GF(p).
-A-MPI
-B-MPI
- The two coefficients of the Weierstrass equation y^2 = x^3 + ax + b
-G-POINT
- Base point g.
-N-MPI
- Order of g
-Q-POINT
- The point representing the public key Q = dG.
-D-MPI
- The private key d
-
- All point values are encoded in standard format; Libgcrypt does in
-general only support uncompressed points, thus the first byte needs to
-be '0x04'. However "EdDSA" describes its own compression scheme which
-is used by default; the non-standard first byte '0x40' may optionally be
-used to explicit flag the use of the algorithm’s native compression
-method.
-
- The public key is similar with "private-key" replaced by "public-key"
-and no D-MPI.
-
- If the domain parameters are well-known, the name of this curve may
-be used. For example
-
- (private-key
- (ecc
- (curve "NIST P-192")
- (q Q-POINT)
- (d D-MPI)))
-
- Note that Q-POINT is optional for a private key. The 'curve'
-parameter may be given in any case and is used to replace missing
-parameters.
-
-Currently implemented curves are:
-'NIST P-192'
-'1.2.840.10045.3.1.1'
-'prime192v1'
-'secp192r1'
- The NIST 192 bit curve, its OID, X9.62 and SECP aliases.
-
-'NIST P-224'
-'secp224r1'
- The NIST 224 bit curve and its SECP alias.
-
-'NIST P-256'
-'1.2.840.10045.3.1.7'
-'prime256v1'
-'secp256r1'
- The NIST 256 bit curve, its OID, X9.62 and SECP aliases.
-
-'NIST P-384'
-'secp384r1'
- The NIST 384 bit curve and its SECP alias.
-
-'NIST P-521'
-'secp521r1'
- The NIST 521 bit curve and its SECP alias.
-
- As usual the OIDs may optionally be prefixed with the string 'OID.'
-or 'oid.'.
-
-\1f
-File: gcrypt.info, Node: Cryptographic Functions, Next: General public-key related Functions, Prev: Used S-expressions, Up: Public Key cryptography
-
-6.3 Cryptographic Functions
-===========================
-
-Some functions operating on S-expressions support 'flags' to influence
-the operation. These flags have to be listed in a sub-S-expression
-named 'flags'. Flag names are case-sensitive. The following flags are
-known:
-
-'comp'
-'nocomp'
- If supported by the algorithm and curve the 'comp' flag requests
- that points are returned in compact (compressed) representation.
- The 'nocomp' flag requests that points are returned with full
- coordinates. The default depends on the the algorithm and curve.
- The compact representation requires a small overhead before a point
- can be used but halves the size of a to be conveyed public key. If
- 'comp' is used with the "EdDSA" algorithm the key generation prefix
- the public key with a '0x40' byte.
-
-'pkcs1'
- Use PKCS#1 block type 2 padding for encryption, block type 1
- padding for signing.
-
-'oaep'
- Use RSA-OAEP padding for encryption.
-
-'pss'
- Use RSA-PSS padding for signing.
-
-'eddsa'
- Use the EdDSA scheme signing instead of the default ECDSA
- algorithm. Note that the EdDSA uses a special form of the public
- key.
-
-'rfc6979'
- For DSA and ECDSA use a deterministic scheme for the k parameter.
-
-'no-blinding'
- Do not use a technique called 'blinding', which is used by default
- in order to prevent leaking of secret information. Blinding is
- only implemented by RSA, but it might be implemented by other
- algorithms in the future as well, when necessary.
-
-'param'
- For ECC key generation also return the domain parameters. For ECC
- signing and verification override default parameters by provided
- domain parameters of the public or private key.
-
-'transient-key'
- This flag is only meaningful for RSA, DSA, and ECC key generation.
- If given the key is created using a faster and a somewhat less
- secure random number generator. This flag may be used for keys
- which are only used for a short time or per-message and do not
- require full cryptographic strength.
-
-'no-keytest'
- This flag skips internal failsafe tests to assert that a generated
- key is properly working. It currently has an effect only for
- standard ECC key generation. It is mostly useful along with
- transient-key to achieve fastest ECC key generation.
-
-'use-x931'
- Force the use of the ANSI X9.31 key generation algorithm instead of
- the default algorithm. This flag is only meaningful for RSA key
- generation and usually not required. Note that this algorithm is
- implicitly used if either 'derive-parms' is given or Libgcrypt is
- in FIPS mode.
-
-'use-fips186'
- Force the use of the FIPS 186 key generation algorithm instead of
- the default algorithm. This flag is only meaningful for DSA and
- usually not required. Note that this algorithm is implicitly used
- if either 'derive-parms' is given or Libgcrypt is in FIPS mode. As
- of now FIPS 186-2 is implemented; after the approval of FIPS 186-3
- the code will be changed to implement 186-3.
-
-'use-fips186-2'
- Force the use of the FIPS 186-2 key generation algorithm instead of
- the default algorithm. This algorithm is slightly different from
- FIPS 186-3 and allows only 1024 bit keys. This flag is only
- meaningful for DSA and only required for FIPS testing backward
- compatibility.
-
-Now that we know the key basics, we can carry on and explain how to
-encrypt and decrypt data. In almost all cases the data is a random
-session key which is in turn used for the actual encryption of the real
-data. There are 2 functions to do this:
-
- -- Function: gcry_error_t gcry_pk_encrypt (gcry_sexp_t *R_CIPH,
- gcry_sexp_t DATA, gcry_sexp_t PKEY)
-
- Obviously a public key must be provided for encryption. It is
- expected as an appropriate S-expression (see above) in PKEY. The
- data to be encrypted can either be in the simple old format, which
- is a very simple S-expression consisting only of one MPI, or it may
- be a more complex S-expression which also allows to specify flags
- for operation, like e.g. padding rules.
-
- If you don't want to let Libgcrypt handle the padding, you must
- pass an appropriate MPI using this expression for DATA:
-
- (data
- (flags raw)
- (value MPI))
-
- This has the same semantics as the old style MPI only way. MPI is
- the actual data, already padded appropriate for your protocol.
- Most RSA based systems however use PKCS#1 padding and so you can
- use this S-expression for DATA:
-
- (data
- (flags pkcs1)
- (value BLOCK))
-
- Here, the "flags" list has the "pkcs1" flag which let the function
- know that it should provide PKCS#1 block type 2 padding. The
- actual data to be encrypted is passed as a string of octets in
- BLOCK. The function checks that this data actually can be used
- with the given key, does the padding and encrypts it.
-
- If the function could successfully perform the encryption, the
- return value will be 0 and a new S-expression with the encrypted
- result is allocated and assigned to the variable at the address of
- R_CIPH. The caller is responsible to release this value using
- 'gcry_sexp_release'. In case of an error, an error code is
- returned and R_CIPH will be set to 'NULL'.
-
- The returned S-expression has this format when used with RSA:
-
- (enc-val
- (rsa
- (a A-MPI)))
-
- Where A-MPI is an MPI with the result of the RSA operation. When
- using the Elgamal algorithm, the return value will have this
- format:
-
- (enc-val
- (elg
- (a A-MPI)
- (b B-MPI)))
-
- Where A-MPI and B-MPI are MPIs with the result of the Elgamal
- encryption operation.
-
- -- Function: gcry_error_t gcry_pk_decrypt (gcry_sexp_t *R_PLAIN,
- gcry_sexp_t DATA, gcry_sexp_t SKEY)
-
- Obviously a private key must be provided for decryption. It is
- expected as an appropriate S-expression (see above) in SKEY. The
- data to be decrypted must match the format of the result as
- returned by 'gcry_pk_encrypt', but should be enlarged with a
- 'flags' element:
-
- (enc-val
- (flags)
- (elg
- (a A-MPI)
- (b B-MPI)))
-
- This function does not remove padding from the data by default. To
- let Libgcrypt remove padding, give a hint in 'flags' telling which
- padding method was used when encrypting:
-
- (flags PADDING-METHOD)
-
- Currently PADDING-METHOD is either 'pkcs1' for PKCS#1 block type 2
- padding, or 'oaep' for RSA-OAEP padding.
-
- The function returns 0 on success or an error code. The variable
- at the address of R_PLAIN will be set to NULL on error or receive
- the decrypted value on success. The format of R_PLAIN is a simple
- S-expression part (i.e. not a valid one) with just one MPI if
- there was no 'flags' element in DATA; if at least an empty 'flags'
- is passed in DATA, the format is:
-
- (value PLAINTEXT)
-
- Another operation commonly performed using public key cryptography is
-signing data. In some sense this is even more important than encryption
-because digital signatures are an important instrument for key
-management. Libgcrypt supports digital signatures using 2 functions,
-similar to the encryption functions:
-
- -- Function: gcry_error_t gcry_pk_sign (gcry_sexp_t *R_SIG,
- gcry_sexp_t DATA, gcry_sexp_t SKEY)
-
- This function creates a digital signature for DATA using the
- private key SKEY and place it into the variable at the address of
- R_SIG. DATA may either be the simple old style S-expression with
- just one MPI or a modern and more versatile S-expression which
- allows to let Libgcrypt handle padding:
-
- (data
- (flags pkcs1)
- (hash HASH-ALGO BLOCK))
-
- This example requests to sign the data in BLOCK after applying
- PKCS#1 block type 1 style padding. HASH-ALGO is a string with the
- hash algorithm to be encoded into the signature, this may be any
- hash algorithm name as supported by Libgcrypt. Most likely, this
- will be "sha256" or "sha1". It is obvious that the length of BLOCK
- must match the size of that message digests; the function checks
- that this and other constraints are valid.
-
- If PKCS#1 padding is not required (because the caller does already
- provide a padded value), either the old format or better the
- following format should be used:
-
- (data
- (flags raw)
- (value MPI))
-
- Here, the data to be signed is directly given as an MPI.
-
- For DSA the input data is expected in this format:
-
- (data
- (flags raw)
- (value MPI))
-
- Here, the data to be signed is directly given as an MPI. It is
- expect that this MPI is the the hash value. For the standard DSA
- using a MPI is not a problem in regard to leading zeroes because
- the hash value is directly used as an MPI. For better standard
- conformance it would be better to explicit use a memory string
- (like with pkcs1) but that is currently not supported. However,
- for deterministic DSA as specified in RFC6979 this can't be used.
- Instead the following input is expected.
-
- (data
- (flags rfc6979)
- (hash HASH-ALGO BLOCK))
-
- Note that the provided hash-algo is used for the internal HMAC; it
- should match the hash-algo used to create BLOCK.
-
- The signature is returned as a newly allocated S-expression in
- R_SIG using this format for RSA:
-
- (sig-val
- (rsa
- (s S-MPI)))
-
- Where S-MPI is the result of the RSA sign operation. For DSA the
- S-expression returned is:
-
- (sig-val
- (dsa
- (r R-MPI)
- (s S-MPI)))
-
- Where R-MPI and S-MPI are the result of the DSA sign operation.
-
- For Elgamal signing (which is slow, yields large numbers and
- probably is not as secure as the other algorithms), the same format
- is used with "elg" replacing "dsa"; for ECDSA signing, the same
- format is used with "ecdsa" replacing "dsa".
-
- For the EdDSA algorithm (cf. Ed25515) the required input
- parameters are:
-
- (data
- (flags eddsa)
- (hash-algo sha512)
- (value MESSAGE))
-
- Note that the MESSAGE may be of any length; hashing is part of the
- algorithm. Using a large data block for MESSAGE is not suggested;
- in that case the used protocol should better require that a hash of
- the message is used as input to the EdDSA algorithm.
-
-The operation most commonly used is definitely the verification of a
-signature. Libgcrypt provides this function:
-
- -- Function: gcry_error_t gcry_pk_verify (gcry_sexp_t SIG,
- gcry_sexp_t DATA, gcry_sexp_t PKEY)
-
- This is used to check whether the signature SIG matches the DATA.
- The public key PKEY must be provided to perform this verification.
- This function is similar in its parameters to 'gcry_pk_sign' with
- the exceptions that the public key is used instead of the private
- key and that no signature is created but a signature, in a format
- as created by 'gcry_pk_sign', is passed to the function in SIG.
-
- The result is 0 for success (i.e. the data matches the signature),
- or an error code where the most relevant code is
- 'GCRY_ERR_BAD_SIGNATURE' to indicate that the signature does not
- match the provided data.
-
-\1f
-File: gcrypt.info, Node: General public-key related Functions, Prev: Cryptographic Functions, Up: Public Key cryptography
-
-6.4 General public-key related Functions
-========================================
-
-A couple of utility functions are available to retrieve the length of
-the key, map algorithm identifiers and perform sanity checks:
-
- -- Function: const char * gcry_pk_algo_name (int ALGO)
-
- Map the public key algorithm id ALGO to a string representation of
- the algorithm name. For unknown algorithms this functions returns
- the string '"?"'. This function should not be used to test for the
- availability of an algorithm.
-
- -- Function: int gcry_pk_map_name (const char *NAME)
-
- Map the algorithm NAME to a public key algorithm Id. Returns 0 if
- the algorithm name is not known.
-
- -- Function: int gcry_pk_test_algo (int ALGO)
-
- Return 0 if the public key algorithm ALGO is available for use.
- Note that this is implemented as a macro.
-
- -- Function: unsigned int gcry_pk_get_nbits (gcry_sexp_t KEY)
-
- Return what is commonly referred as the key length for the given
- public or private in KEY.
-
- -- Function: unsigned char * gcry_pk_get_keygrip (gcry_sexp_t KEY,
- unsigned char *ARRAY)
-
- Return the so called "keygrip" which is the SHA-1 hash of the
- public key parameters expressed in a way depended on the algorithm.
- ARRAY must either provide space for 20 bytes or be 'NULL'. In the
- latter case a newly allocated array of that size is returned. On
- success a pointer to the newly allocated space or to ARRAY is
- returned. 'NULL' is returned to indicate an error which is most
- likely an unknown algorithm or one where a "keygrip" has not yet
- been defined. The function accepts public or secret keys in KEY.
-
- -- Function: gcry_error_t gcry_pk_testkey (gcry_sexp_t KEY)
-
- Return zero if the private key KEY is 'sane', an error code
- otherwise. Note that it is not possible to check the 'saneness' of
- a public key.
-
- -- Function: gcry_error_t gcry_pk_algo_info (int ALGO, int WHAT,
- void *BUFFER, size_t *NBYTES)
-
- Depending on the value of WHAT return various information about the
- public key algorithm with the id ALGO. Note that the function
- returns '-1' on error and the actual error code must be retrieved
- using the function 'gcry_errno'. The currently defined values for
- WHAT are:
-
- 'GCRYCTL_TEST_ALGO:'
- Return 0 if the specified algorithm is available for use.
- BUFFER must be 'NULL', NBYTES may be passed as 'NULL' or point
- to a variable with the required usage of the algorithm. This
- may be 0 for "don't care" or the bit-wise OR of these flags:
-
- 'GCRY_PK_USAGE_SIGN'
- Algorithm is usable for signing.
- 'GCRY_PK_USAGE_ENCR'
- Algorithm is usable for encryption.
-
- Unless you need to test for the allowed usage, it is in
- general better to use the macro gcry_pk_test_algo instead.
-
- 'GCRYCTL_GET_ALGO_USAGE:'
- Return the usage flags for the given algorithm. An invalid
- algorithm return 0. Disabled algorithms are ignored here
- because we want to know whether the algorithm is at all
- capable of a certain usage.
-
- 'GCRYCTL_GET_ALGO_NPKEY'
- Return the number of elements the public key for algorithm
- ALGO consist of. Return 0 for an unknown algorithm.
-
- 'GCRYCTL_GET_ALGO_NSKEY'
- Return the number of elements the private key for algorithm
- ALGO consist of. Note that this value is always larger than
- that of the public key. Return 0 for an unknown algorithm.
-
- 'GCRYCTL_GET_ALGO_NSIGN'
- Return the number of elements a signature created with the
- algorithm ALGO consists of. Return 0 for an unknown algorithm
- or for an algorithm not capable of creating signatures.
-
- 'GCRYCTL_GET_ALGO_NENC'
- Return the number of elements a encrypted message created with
- the algorithm ALGO consists of. Return 0 for an unknown
- algorithm or for an algorithm not capable of encryption.
-
- Please note that parameters not required should be passed as
- 'NULL'.
-
- -- Function: gcry_error_t gcry_pk_ctl (int CMD, void *BUFFER,
- size_t BUFLEN)
-
- This is a general purpose function to perform certain control
- operations. CMD controls what is to be done. The return value is
- 0 for success or an error code. Currently supported values for CMD
- are:
-
- 'GCRYCTL_DISABLE_ALGO'
- Disable the algorithm given as an algorithm id in BUFFER.
- BUFFER must point to an 'int' variable with the algorithm id
- and BUFLEN must have the value 'sizeof (int)'. This function
- is not thread safe and should thus be used before any other
- threads are started.
-
-Libgcrypt also provides a function to generate public key pairs:
-
- -- Function: gcry_error_t gcry_pk_genkey (gcry_sexp_t *R_KEY,
- gcry_sexp_t PARMS)
-
- This function create a new public key pair using information given
- in the S-expression PARMS and stores the private and the public key
- in one new S-expression at the address given by R_KEY. In case of
- an error, R_KEY is set to 'NULL'. The return code is 0 for success
- or an error code otherwise.
-
- Here is an example for PARMS to create an 2048 bit RSA key:
-
- (genkey
- (rsa
- (nbits 4:2048)))
-
- To create an Elgamal key, substitute "elg" for "rsa" and to create
- a DSA key use "dsa". Valid ranges for the key length depend on the
- algorithms; all commonly used key lengths are supported. Currently
- supported parameters are:
-
- 'nbits'
- This is always required to specify the length of the key. The
- argument is a string with a number in C-notation. The value
- should be a multiple of 8. Note that the S-expression syntax
- requires that a number is prefixed with its string length;
- thus the '4:' in the above example.
-
- 'curve NAME'
- For ECC a named curve may be used instead of giving the number
- of requested bits. This allows to request a specific curve to
- override a default selection Libgcrypt would have taken if
- 'nbits' has been given. The available names are listed with
- the description of the ECC public key parameters.
-
- 'rsa-use-e VALUE'
- This is only used with RSA to give a hint for the public
- exponent. The VALUE will be used as a base to test for a
- usable exponent. Some values are special:
-
- '0'
- Use a secure and fast value. This is currently the
- number 41.
- '1'
- Use a value as required by some crypto policies. This is
- currently the number 65537.
- '2'
- Reserved
- '> 2'
- Use the given value.
-
- If this parameter is not used, Libgcrypt uses for historic
- reasons 65537.
-
- 'qbits N'
- This is only meanigful for DSA keys. If it is given the DSA
- key is generated with a Q parameyer of size N bits. If it is
- not given or zero Q is deduced from NBITS in this way:
- '512 <= N <= 1024'
- Q = 160
- 'N = 2048'
- Q = 224
- 'N = 3072'
- Q = 256
- 'N = 7680'
- Q = 384
- 'N = 15360'
- Q = 512
- Note that in this case only the values for N, as given in the
- table, are allowed. When specifying Q all values of N in the
- range 512 to 15680 are valid as long as they are multiples of
- 8.
-
- 'domain LIST'
- This is only meaningful for DLP algorithms. If specified keys
- are generated with domain parameters taken from this list.
- The exact format of this parameter depends on the actual
- algorithm. It is currently only implemented for DSA using
- this format:
-
- (genkey
- (dsa
- (domain
- (p P-MPI)
- (q Q-MPI)
- (g Q-MPI))))
-
- 'nbits' and 'qbits' may not be specified because they are
- derived from the domain parameters.
-
- 'derive-parms LIST'
- This is currently only implemented for RSA and DSA keys. It
- is not allowed to use this together with a 'domain'
- specification. If given, it is used to derive the keys using
- the given parameters.
-
- If given for an RSA key the X9.31 key generation algorithm is
- used even if libgcrypt is not in FIPS mode. If given for a
- DSA key, the FIPS 186 algorithm is used even if libgcrypt is
- not in FIPS mode.
-
- (genkey
- (rsa
- (nbits 4:1024)
- (rsa-use-e 1:3)
- (derive-parms
- (Xp1 #1A1916DDB29B4EB7EB6732E128#)
- (Xp2 #192E8AAC41C576C822D93EA433#)
- (Xp #D8CD81F035EC57EFE822955149D3BFF70C53520D
- 769D6D76646C7A792E16EBD89FE6FC5B605A6493
- 39DFC925A86A4C6D150B71B9EEA02D68885F5009
- B98BD984#)
- (Xq1 #1A5CF72EE770DE50CB09ACCEA9#)
- (Xq2 #134E4CAA16D2350A21D775C404#)
- (Xq #CC1092495D867E64065DEE3E7955F2EBC7D47A2D
- 7C9953388F97DDDC3E1CA19C35CA659EDC2FC325
- 6D29C2627479C086A699A49C4C9CEE7EF7BD1B34
- 321DE34A#))))
-
- (genkey
- (dsa
- (nbits 4:1024)
- (derive-parms
- (seed SEED-MPI))))
-
- 'flags FLAGLIST'
- This is preferred way to define flags. FLAGLIST may contain
- any number of flags. See above for a specification of these
- flags.
-
- Here is an example on how to create a key using curve Ed25519
- with the ECDSA signature algorithm. Note that the use of
- ECDSA with that curve is in general not recommended.
- (genkey
- (ecc
- (flags transient-key)))
-
- 'transient-key'
- 'use-x931'
- 'use-fips186'
- 'use-fips186-2'
- These are deprecated ways to set a flag with that name; see
- above for a description of each flag.
-
- The key pair is returned in a format depending on the algorithm.
- Both private and public keys are returned in one container and may
- be accompanied by some miscellaneous information.
-
- Here are two examples; the first for Elgamal and the second for
- elliptic curve key generation:
-
- (key-data
- (public-key
- (elg
- (p P-MPI)
- (g G-MPI)
- (y Y-MPI)))
- (private-key
- (elg
- (p P-MPI)
- (g G-MPI)
- (y Y-MPI)
- (x X-MPI)))
- (misc-key-info
- (pm1-factors N1 N2 ... NN))
-
- (key-data
- (public-key
- (ecc
- (curve Ed25519)
- (flags eddsa)
- (q Q-VALUE)))
- (private-key
- (ecc
- (curve Ed25519)
- (flags eddsa)
- (q Q-VALUE)
- (d D-VALUE))))
-
- As you can see, some of the information is duplicated, but this
- provides an easy way to extract either the public or the private
- key. Note that the order of the elements is not defined, e.g. the
- private key may be stored before the public key. N1 N2 ... NN is a
- list of prime numbers used to composite P-MPI; this is in general
- not a very useful information and only available if the key
- generation algorithm provides them.
-
-Future versions of Libgcrypt will have extended versions of the public
-key interfaced which will take an additional context to allow for
-pre-computations, special operations, and other optimization. As a
-first step a new function is introduced to help using the ECC algorithms
-in new ways:
-
- -- Function: gcry_error_t gcry_pubkey_get_sexp (gcry_sexp_t *R_SEXP,
- int MODE, gcry_ctx_t CTX)
-
- Return an S-expression representing the context CTX. Depending on
- the state of that context, the S-expression may either be a public
- key, a private key or any other object used with public key
- operations. On success 0 is returned and a new S-expression is
- stored at R_SEXP; on error an error code is returned and NULL is
- stored at R_SEXP. MODE must be one of:
-
- '0'
- Decide what to return depending on the context. For example
- if the private key parameter is available a private key is
- returned, if not a public key is returned.
-
- 'GCRY_PK_GET_PUBKEY'
- Return the public key even if the context has the private key
- parameter.
-
- 'GCRY_PK_GET_SECKEY'
- Return the private key or the error 'GPG_ERR_NO_SECKEY' if it
- is not possible.
-
- As of now this function supports only certain ECC operations
- because a context object is right now only defined for ECC. Over
- time this function will be extended to cover more algorithms.
-
-\1f
-File: gcrypt.info, Node: Hashing, Next: Message Authentication Codes, Prev: Public Key cryptography, Up: Top
-
-7 Hashing
-*********
-
-Libgcrypt provides an easy and consistent to use interface for hashing.
-Hashing is buffered and several hash algorithms can be updated at once.
-It is possible to compute a HMAC using the same routines. The
-programming model follows an open/process/close paradigm and is in that
-similar to other building blocks provided by Libgcrypt.
-
- For convenience reasons, a few cyclic redundancy check value
-operations are also supported.
-
-* Menu:
-
-* Available hash algorithms:: List of hash algorithms supported by the library.
-* Working with hash algorithms:: List of functions related to hashing.
-
-\1f
-File: gcrypt.info, Node: Available hash algorithms, Next: Working with hash algorithms, Up: Hashing
-
-7.1 Available hash algorithms
-=============================
-
-'GCRY_MD_NONE'
- This is not a real algorithm but used by some functions as an error
- return value. This constant is guaranteed to have the value '0'.
-
-'GCRY_MD_SHA1'
- This is the SHA-1 algorithm which yields a message digest of 20
- bytes. Note that SHA-1 begins to show some weaknesses and it is
- suggested to fade out its use if strong cryptographic properties
- are required.
-
-'GCRY_MD_RMD160'
- This is the 160 bit version of the RIPE message digest
- (RIPE-MD-160). Like SHA-1 it also yields a digest of 20 bytes.
- This algorithm share a lot of design properties with SHA-1 and thus
- it is advisable not to use it for new protocols.
-
-'GCRY_MD_MD5'
- This is the well known MD5 algorithm, which yields a message digest
- of 16 bytes. Note that the MD5 algorithm has severe weaknesses,
- for example it is easy to compute two messages yielding the same
- hash (collision attack). The use of this algorithm is only
- justified for non-cryptographic application.
-
-'GCRY_MD_MD4'
- This is the MD4 algorithm, which yields a message digest of 16
- bytes. This algorithm has severe weaknesses and should not be
- used.
-
-'GCRY_MD_MD2'
- This is an reserved identifier for MD-2; there is no implementation
- yet. This algorithm has severe weaknesses and should not be used.
-
-'GCRY_MD_TIGER'
- This is the TIGER/192 algorithm which yields a message digest of 24
- bytes. Actually this is a variant of TIGER with a different output
- print order as used by GnuPG up to version 1.3.2.
-
-'GCRY_MD_TIGER1'
- This is the TIGER variant as used by the NESSIE project. It uses
- the most commonly used output print order.
-
-'GCRY_MD_TIGER2'
- This is another variant of TIGER with a different padding scheme.
-
-'GCRY_MD_HAVAL'
- This is an reserved value for the HAVAL algorithm with 5 passes and
- 160 bit. It yields a message digest of 20 bytes. Note that there
- is no implementation yet available.
-
-'GCRY_MD_SHA224'
- This is the SHA-224 algorithm which yields a message digest of 28
- bytes. See Change Notice 1 for FIPS 180-2 for the specification.
-
-'GCRY_MD_SHA256'
- This is the SHA-256 algorithm which yields a message digest of 32
- bytes. See FIPS 180-2 for the specification.
-
-'GCRY_MD_SHA384'
- This is the SHA-384 algorithm which yields a message digest of 48
- bytes. See FIPS 180-2 for the specification.
-
-'GCRY_MD_SHA512'
- This is the SHA-384 algorithm which yields a message digest of 64
- bytes. See FIPS 180-2 for the specification.
-
-'GCRY_MD_SHA3_224'
- This is the SHA3-224 algorithm which yields a message digest of 28
- bytes. See FIPS 202 for the specification.
-
-'GCRY_MD_SHA3_256'
- This is the SHA3-256 algorithm which yields a message digest of 32
- bytes. See FIPS 202 for the specification.
-
-'GCRY_MD_SHA3_384'
- This is the SHA3-384 algorithm which yields a message digest of 48
- bytes. See FIPS 202 for the specification.
-
-'GCRY_MD_SHA3_512'
- This is the SHA3-384 algorithm which yields a message digest of 64
- bytes. See FIPS 202 for the specification.
-
-'GCRY_MD_SHAKE128'
- This is the SHAKE128 extendable-output function (XOF) algorithm
- with 128 bit security strength. See FIPS 202 for the
- specification.
-
-'GCRY_MD_SHAKE256'
- This is the SHAKE256 extendable-output function (XOF) algorithm
- with 256 bit security strength. See FIPS 202 for the
- specification.
-
-'GCRY_MD_CRC32'
- This is the ISO 3309 and ITU-T V.42 cyclic redundancy check. It
- yields an output of 4 bytes. Note that this is not a hash
- algorithm in the cryptographic sense.
-
-'GCRY_MD_CRC32_RFC1510'
- This is the above cyclic redundancy check function, as modified by
- RFC 1510. It yields an output of 4 bytes. Note that this is not a
- hash algorithm in the cryptographic sense.
-
-'GCRY_MD_CRC24_RFC2440'
- This is the OpenPGP cyclic redundancy check function. It yields an
- output of 3 bytes. Note that this is not a hash algorithm in the
- cryptographic sense.
-
-'GCRY_MD_WHIRLPOOL'
- This is the Whirlpool algorithm which yields a message digest of 64
- bytes.
-
-'GCRY_MD_GOSTR3411_94'
- This is the hash algorithm described in GOST R 34.11-94 which
- yields a message digest of 32 bytes.
-
-'GCRY_MD_STRIBOG256'
- This is the 256-bit version of hash algorithm described in GOST R
- 34.11-2012 which yields a message digest of 32 bytes.
-
-'GCRY_MD_STRIBOG512'
- This is the 512-bit version of hash algorithm described in GOST R
- 34.11-2012 which yields a message digest of 64 bytes.
-
-'GCRY_MD_BLAKE2B_512'
- This is the BLAKE2b-512 algorithm which yields a message digest of
- 64 bytes. See RFC 7693 for the specification.
-
-'GCRY_MD_BLAKE2B_384'
- This is the BLAKE2b-384 algorithm which yields a message digest of
- 48 bytes. See RFC 7693 for the specification.
-
-'GCRY_MD_BLAKE2B_256'
- This is the BLAKE2b-256 algorithm which yields a message digest of
- 32 bytes. See RFC 7693 for the specification.
-
-'GCRY_MD_BLAKE2B_160'
- This is the BLAKE2b-160 algorithm which yields a message digest of
- 20 bytes. See RFC 7693 for the specification.
-
-'GCRY_MD_BLAKE2S_256'
- This is the BLAKE2s-256 algorithm which yields a message digest of
- 32 bytes. See RFC 7693 for the specification.
-
-'GCRY_MD_BLAKE2S_224'
- This is the BLAKE2s-224 algorithm which yields a message digest of
- 28 bytes. See RFC 7693 for the specification.
-
-'GCRY_MD_BLAKE2S_160'
- This is the BLAKE2s-160 algorithm which yields a message digest of
- 20 bytes. See RFC 7693 for the specification.
-
-'GCRY_MD_BLAKE2S_128'
- This is the BLAKE2s-128 algorithm which yields a message digest of
- 16 bytes. See RFC 7693 for the specification.
-
-\1f
-File: gcrypt.info, Node: Working with hash algorithms, Prev: Available hash algorithms, Up: Hashing
-
-7.2 Working with hash algorithms
-================================
-
-To use most of these function it is necessary to create a context; this
-is done using:
-
- -- Function: gcry_error_t gcry_md_open (gcry_md_hd_t *HD, int ALGO,
- unsigned int FLAGS)
-
- Create a message digest object for algorithm ALGO. FLAGS may be
- given as an bitwise OR of constants described below. ALGO may be
- given as '0' if the algorithms to use are later set using
- 'gcry_md_enable'. HD is guaranteed to either receive a valid
- handle or NULL.
-
- For a list of supported algorithms, see *Note Available hash
- algorithms::.
-
- The flags allowed for MODE are:
-
- 'GCRY_MD_FLAG_SECURE'
- Allocate all buffers and the resulting digest in "secure
- memory". Use this is the hashed data is highly confidential.
-
- 'GCRY_MD_FLAG_HMAC'
- Turn the algorithm into a HMAC message authentication
- algorithm. This only works if just one algorithm is enabled
- for the handle and that algorithm is not an extendable-output
- function. Note that the function 'gcry_md_setkey' must be
- used to set the MAC key. The size of the MAC is equal to the
- message digest of the underlying hash algorithm. If you want
- CBC message authentication codes based on a cipher, see *Note
- Working with cipher handles::.
-
- 'GCRY_MD_FLAG_BUGEMU1'
- Versions of Libgcrypt before 1.6.0 had a bug in the Whirlpool
- code which led to a wrong result for certain input sizes and
- write patterns. Using this flag emulates that bug. This may
- for example be useful for applications which use Whirlpool as
- part of their key generation. It is strongly suggested to use
- this flag only if really needed and if possible to the data
- should be re-processed using the regular Whirlpool algorithm.
-
- Note that this flag works for the entire hash context. If
- needed arises it may be used to enable bug emulation for other
- hash algorithms. Thus you should not use this flag for a
- multi-algorithm hash context.
-
- You may use the function 'gcry_md_is_enabled' to later check
- whether an algorithm has been enabled.
-
- If you want to calculate several hash algorithms at the same time,
-you have to use the following function right after the 'gcry_md_open':
-
- -- Function: gcry_error_t gcry_md_enable (gcry_md_hd_t H, int ALGO)
-
- Add the message digest algorithm ALGO to the digest object
- described by handle H. Duplicated enabling of algorithms is
- detected and ignored.
-
- If the flag 'GCRY_MD_FLAG_HMAC' was used, the key for the MAC must be
-set using the function:
-
- -- Function: gcry_error_t gcry_md_setkey (gcry_md_hd_t H, const void
- *KEY, size_t KEYLEN)
-
- For use with the HMAC feature or BLAKE2 keyed hash, set the MAC key
- to the value of KEY of length KEYLEN bytes. For HMAC, there is no
- restriction on the length of the key. For keyed BLAKE2b hash,
- length of the key must be 64 bytes or less. For keyed BLAKE2s
- hash, length of the key must be 32 bytes or less.
-
- After you are done with the hash calculation, you should release the
-resources by using:
-
- -- Function: void gcry_md_close (gcry_md_hd_t H)
-
- Release all resources of hash context H. H should not be used
- after a call to this function. A 'NULL' passed as H is ignored.
- The function also zeroises all sensitive information associated
- with this handle.
-
- Often you have to do several hash operations using the same
-algorithm. To avoid the overhead of creating and releasing context, a
-reset function is provided:
-
- -- Function: void gcry_md_reset (gcry_md_hd_t H)
-
- Reset the current context to its initial state. This is
- effectively identical to a close followed by an open and enabling
- all currently active algorithms.
-
- Often it is necessary to start hashing some data and then continue to
-hash different data. To avoid hashing the same data several times
-(which might not even be possible if the data is received from a pipe),
-a snapshot of the current hash context can be taken and turned into a
-new context:
-
- -- Function: gcry_error_t gcry_md_copy (gcry_md_hd_t *HANDLE_DST,
- gcry_md_hd_t HANDLE_SRC)
-
- Create a new digest object as an exact copy of the object described
- by handle HANDLE_SRC and store it in HANDLE_DST. The context is
- not reset and you can continue to hash data using this context and
- independently using the original context.
-
- Now that we have prepared everything to calculate hashes, it is time
-to see how it is actually done. There are two ways for this, one to
-update the hash with a block of memory and one macro to update the hash
-by just one character. Both methods can be used on the same hash
-context.
-
- -- Function: void gcry_md_write (gcry_md_hd_t H, const void *BUFFER,
- size_t LENGTH)
-
- Pass LENGTH bytes of the data in BUFFER to the digest object with
- handle H to update the digest values. This function should be used
- for large blocks of data. If this function is used after the
- context has been finalized, it will keep on pushing the data
- through the algorithm specific transform function and change the
- context; however the results are not meaningful and this feature is
- only available to mitigate timing attacks.
-
- -- Function: void gcry_md_putc (gcry_md_hd_t H, int C)
-
- Pass the byte in C to the digest object with handle H to update the
- digest value. This is an efficient function, implemented as a
- macro to buffer the data before an actual update.
-
- The semantics of the hash functions do not provide for reading out
-intermediate message digests because the calculation must be finalized
-first. This finalization may for example include the number of bytes
-hashed in the message digest or some padding.
-
- -- Function: void gcry_md_final (gcry_md_hd_t H)
-
- Finalize the message digest calculation. This is not really needed
- because 'gcry_md_read' and 'gcry_md_extract' do this implicitly.
- After this has been done no further updates (by means of
- 'gcry_md_write' or 'gcry_md_putc' should be done; However, to
- mitigate timing attacks it is sometimes useful to keep on updating
- the context after having stored away the actual digest. Only the
- first call to this function has an effect. It is implemented as a
- macro.
-
- The way to read out the calculated message digest is by using the
-function:
-
- -- Function: unsigned char * gcry_md_read (gcry_md_hd_t H, int ALGO)
-
- 'gcry_md_read' returns the message digest after finalizing the
- calculation. This function may be used as often as required but it
- will always return the same value for one handle. The returned
- message digest is allocated within the message context and
- therefore valid until the handle is released or reset-ed (using
- 'gcry_md_close' or 'gcry_md_reset' or it has been updated as a
- mitigation measure against timing attacks. ALGO may be given as 0
- to return the only enabled message digest or it may specify one of
- the enabled algorithms. The function does return 'NULL' if the
- requested algorithm has not been enabled.
-
- The way to read output of extendable-output function is by using the
-function:
-
- -- Function: gpg_err_code_t gcry_md_extract (gcry_md_hd_t H, int ALGO,
- void *BUFFER, size_t LENGTH)
-
- 'gcry_mac_read' returns output from extendable-output function.
- This function may be used as often as required to generate more
- output byte stream from the algorithm. Function extracts the new
- output bytes to BUFFER of the length LENGTH. Buffer will be fully
- populated with new output. ALGO may be given as 0 to return the
- only enabled message digest or it may specify one of the enabled
- algorithms. The function does return non-zero value if the
- requested algorithm has not been enabled.
-
- Because it is often necessary to get the message digest of blocks of
-memory, two fast convenience function are available for this task:
-
- -- Function: gpg_err_code_t gcry_md_hash_buffers ( int ALGO,
- unsigned int FLAGS, void *DIGEST, const gcry_buffer_t *IOV,
- int IOVCNT )
-
- 'gcry_md_hash_buffers' is a shortcut function to calculate a
- message digest from several buffers. This function does not
- require a context and immediately returns the message digest of the
- data described by IOV and IOVCNT. DIGEST must be allocated by the
- caller, large enough to hold the message digest yielded by the the
- specified algorithm ALGO. This required size may be obtained by
- using the function 'gcry_md_get_algo_dlen'.
-
- IOV is an array of buffer descriptions with IOVCNT items. The
- caller should zero out the structures in this array and for each
- array item set the fields '.data' to the address of the data to be
- hashed, '.len' to number of bytes to be hashed. If .OFF is also
- set, the data is taken starting at .OFF bytes from the begin of the
- buffer. The field '.size' is not used.
-
- The only supported flag value for FLAGS is GCRY_MD_FLAG_HMAC which
- turns this function into a HMAC function; the first item in IOV is
- then used as the key.
-
- On success the function returns 0 and stores the resulting hash or
- MAC at DIGEST.
-
- -- Function: void gcry_md_hash_buffer (int ALGO, void *DIGEST, const
- void *BUFFER, size_t LENGTH);
-
- 'gcry_md_hash_buffer' is a shortcut function to calculate a message
- digest of a buffer. This function does not require a context and
- immediately returns the message digest of the LENGTH bytes at
- BUFFER. DIGEST must be allocated by the caller, large enough to
- hold the message digest yielded by the the specified algorithm
- ALGO. This required size may be obtained by using the function
- 'gcry_md_get_algo_dlen'.
-
- Note that in contrast to 'gcry_md_hash_buffers' this function will
- abort the process if an unavailable algorithm is used.
-
- Hash algorithms are identified by internal algorithm numbers (see
-'gcry_md_open' for a list). However, in most applications they are used
-by names, so two functions are available to map between string
-representations and hash algorithm identifiers.
-
- -- Function: const char * gcry_md_algo_name (int ALGO)
-
- Map the digest algorithm id ALGO to a string representation of the
- algorithm name. For unknown algorithms this function returns the
- string '"?"'. This function should not be used to test for the
- availability of an algorithm.
-
- -- Function: int gcry_md_map_name (const char *NAME)
-
- Map the algorithm with NAME to a digest algorithm identifier.
- Returns 0 if the algorithm name is not known. Names representing
- ASN.1 object identifiers are recognized if the IETF dotted format
- is used and the OID is prefixed with either "'oid.'" or "'OID.'".
- For a list of supported OIDs, see the source code at 'cipher/md.c'.
- This function should not be used to test for the availability of an
- algorithm.
-
- -- Function: gcry_error_t gcry_md_get_asnoid (int ALGO, void *BUFFER,
- size_t *LENGTH)
-
- Return an DER encoded ASN.1 OID for the algorithm ALGO in the user
- allocated BUFFER. LENGTH must point to variable with the available
- size of BUFFER and receives after return the actual size of the
- returned OID. The returned error code may be 'GPG_ERR_TOO_SHORT' if
- the provided buffer is to short to receive the OID; it is possible
- to call the function with 'NULL' for BUFFER to have it only return
- the required size. The function returns 0 on success.
-
- To test whether an algorithm is actually available for use, the
-following macro should be used:
-
- -- Function: gcry_error_t gcry_md_test_algo (int ALGO)
-
- The macro returns 0 if the algorithm ALGO is available for use.
-
- If the length of a message digest is not known, it can be retrieved
-using the following function:
-
- -- Function: unsigned int gcry_md_get_algo_dlen (int ALGO)
-
- Retrieve the length in bytes of the digest yielded by algorithm
- ALGO. This is often used prior to 'gcry_md_read' to allocate
- sufficient memory for the digest.
-
- In some situations it might be hard to remember the algorithm used
-for the ongoing hashing. The following function might be used to get
-that information:
-
- -- Function: int gcry_md_get_algo (gcry_md_hd_t H)
-
- Retrieve the algorithm used with the handle H. Note that this does
- not work reliable if more than one algorithm is enabled in H.
-
- The following macro might also be useful:
-
- -- Function: int gcry_md_is_secure (gcry_md_hd_t H)
-
- This function returns true when the digest object H is allocated in
- "secure memory"; i.e. H was created with the
- 'GCRY_MD_FLAG_SECURE'.
-
- -- Function: int gcry_md_is_enabled (gcry_md_hd_t H, int ALGO)
-
- This function returns true when the algorithm ALGO has been enabled
- for the digest object H.
-
- Tracking bugs related to hashing is often a cumbersome task which
-requires to add a lot of printf statements into the code. Libgcrypt
-provides an easy way to avoid this. The actual data hashed can be
-written to files on request.
-
- -- Function: void gcry_md_debug (gcry_md_hd_t H, const char *SUFFIX)
-
- Enable debugging for the digest object with handle H. This creates
- files named 'dbgmd-<n>.<string>' while doing the actual hashing.
- SUFFIX is the string part in the filename. The number is a counter
- incremented for each new hashing. The data in the file is the raw
- data as passed to 'gcry_md_write' or 'gcry_md_putc'. If 'NULL' is
- used for SUFFIX, the debugging is stopped and the file closed.
- This is only rarely required because 'gcry_md_close' implicitly
- stops debugging.
-
-\1f
-File: gcrypt.info, Node: Message Authentication Codes, Next: Key Derivation, Prev: Hashing, Up: Top
-
-8 Message Authentication Codes
-******************************
-
-Libgcrypt provides an easy and consistent to use interface for
-generating Message Authentication Codes (MAC). MAC generation is
-buffered and interface similar to the one used with hash algorithms.
-The programming model follows an open/process/close paradigm and is in
-that similar to other building blocks provided by Libgcrypt.
-
-* Menu:
-
-* Available MAC algorithms:: List of MAC algorithms supported by the library.
-* Working with MAC algorithms:: List of functions related to MAC algorithms.
-
-\1f
-File: gcrypt.info, Node: Available MAC algorithms, Next: Working with MAC algorithms, Up: Message Authentication Codes
-
-8.1 Available MAC algorithms
-============================
-
-'GCRY_MAC_NONE'
- This is not a real algorithm but used by some functions as an error
- return value. This constant is guaranteed to have the value '0'.
-
-'GCRY_MAC_HMAC_SHA256'
- This is keyed-hash message authentication code (HMAC) message
- authentication algorithm based on the SHA-256 hash algorithm.
-
-'GCRY_MAC_HMAC_SHA224'
- This is HMAC message authentication algorithm based on the SHA-224
- hash algorithm.
-
-'GCRY_MAC_HMAC_SHA512'
- This is HMAC message authentication algorithm based on the SHA-512
- hash algorithm.
-
-'GCRY_MAC_HMAC_SHA384'
- This is HMAC message authentication algorithm based on the SHA-384
- hash algorithm.
-
-'GCRY_MAC_HMAC_SHA3_256'
- This is HMAC message authentication algorithm based on the SHA3-384
- hash algorithm.
-
-'GCRY_MAC_HMAC_SHA3_224'
- This is HMAC message authentication algorithm based on the SHA3-224
- hash algorithm.
-
-'GCRY_MAC_HMAC_SHA3_512'
- This is HMAC message authentication algorithm based on the SHA3-512
- hash algorithm.
-
-'GCRY_MAC_HMAC_SHA3_384'
- This is HMAC message authentication algorithm based on the SHA3-384
- hash algorithm.
-
-'GCRY_MAC_HMAC_SHA1'
- This is HMAC message authentication algorithm based on the SHA-1
- hash algorithm.
-
-'GCRY_MAC_HMAC_MD5'
- This is HMAC message authentication algorithm based on the MD5 hash
- algorithm.
-
-'GCRY_MAC_HMAC_MD4'
- This is HMAC message authentication algorithm based on the MD4 hash
- algorithm.
-
-'GCRY_MAC_HMAC_RMD160'
- This is HMAC message authentication algorithm based on the
- RIPE-MD-160 hash algorithm.
-
-'GCRY_MAC_HMAC_WHIRLPOOL'
- This is HMAC message authentication algorithm based on the
- WHIRLPOOL hash algorithm.
-
-'GCRY_MAC_HMAC_GOSTR3411_94'
- This is HMAC message authentication algorithm based on the GOST R
- 34.11-94 hash algorithm.
-
-'GCRY_MAC_HMAC_STRIBOG256'
- This is HMAC message authentication algorithm based on the 256-bit
- hash algorithm described in GOST R 34.11-2012.
-
-'GCRY_MAC_HMAC_STRIBOG512'
- This is HMAC message authentication algorithm based on the 512-bit
- hash algorithm described in GOST R 34.11-2012.
-
-'GCRY_MAC_CMAC_AES'
- This is CMAC (Cipher-based MAC) message authentication algorithm
- based on the AES block cipher algorithm.
-
-'GCRY_MAC_CMAC_3DES'
- This is CMAC message authentication algorithm based on the
- three-key EDE Triple-DES block cipher algorithm.
-
-'GCRY_MAC_CMAC_CAMELLIA'
- This is CMAC message authentication algorithm based on the Camellia
- block cipher algorithm.
-
-'GCRY_MAC_CMAC_CAST5'
- This is CMAC message authentication algorithm based on the
- CAST128-5 block cipher algorithm.
-
-'GCRY_MAC_CMAC_BLOWFISH'
- This is CMAC message authentication algorithm based on the Blowfish
- block cipher algorithm.
-
-'GCRY_MAC_CMAC_TWOFISH'
- This is CMAC message authentication algorithm based on the Twofish
- block cipher algorithm.
-
-'GCRY_MAC_CMAC_SERPENT'
- This is CMAC message authentication algorithm based on the Serpent
- block cipher algorithm.
-
-'GCRY_MAC_CMAC_SEED'
- This is CMAC message authentication algorithm based on the SEED
- block cipher algorithm.
-
-'GCRY_MAC_CMAC_RFC2268'
- This is CMAC message authentication algorithm based on the Ron's
- Cipher 2 block cipher algorithm.
-
-'GCRY_MAC_CMAC_IDEA'
- This is CMAC message authentication algorithm based on the IDEA
- block cipher algorithm.
-
-'GCRY_MAC_CMAC_GOST28147'
- This is CMAC message authentication algorithm based on the GOST
- 28147-89 block cipher algorithm.
-
-'GCRY_MAC_GMAC_AES'
- This is GMAC (GCM mode based MAC) message authentication algorithm
- based on the AES block cipher algorithm.
-
-'GCRY_MAC_GMAC_CAMELLIA'
- This is GMAC message authentication algorithm based on the Camellia
- block cipher algorithm.
-
-'GCRY_MAC_GMAC_TWOFISH'
- This is GMAC message authentication algorithm based on the Twofish
- block cipher algorithm.
-
-'GCRY_MAC_GMAC_SERPENT'
- This is GMAC message authentication algorithm based on the Serpent
- block cipher algorithm.
-
-'GCRY_MAC_GMAC_SEED'
- This is GMAC message authentication algorithm based on the SEED
- block cipher algorithm.
-
-'GCRY_MAC_POLY1305'
- This is plain Poly1305 message authentication algorithm, used with
- one-time key.
-
-'GCRY_MAC_POLY1305_AES'
- This is Poly1305-AES message authentication algorithm, used with
- key and one-time nonce.
-
-'GCRY_MAC_POLY1305_CAMELLIA'
- This is Poly1305-Camellia message authentication algorithm, used
- with key and one-time nonce.
-
-'GCRY_MAC_POLY1305_TWOFISH'
- This is Poly1305-Twofish message authentication algorithm, used
- with key and one-time nonce.
-
-'GCRY_MAC_POLY1305_SERPENT'
- This is Poly1305-Serpent message authentication algorithm, used
- with key and one-time nonce.
-
-'GCRY_MAC_POLY1305_SEED'
- This is Poly1305-SEED message authentication algorithm, used with
- key and one-time nonce.
-
-\1f
-File: gcrypt.info, Node: Working with MAC algorithms, Prev: Available MAC algorithms, Up: Message Authentication Codes
-
-8.2 Working with MAC algorithms
-===============================
-
-To use most of these function it is necessary to create a context; this
-is done using:
-
- -- Function: gcry_error_t gcry_mac_open (gcry_mac_hd_t *HD, int ALGO,
- unsigned int FLAGS, gcry_ctx_t CTX)
-
- Create a MAC object for algorithm ALGO. FLAGS may be given as an
- bitwise OR of constants described below. HD is guaranteed to
- either receive a valid handle or NULL. CTX is context object to
- associate MAC object with. CTX maybe set to NULL.
-
- For a list of supported algorithms, see *Note Available MAC
- algorithms::.
-
- The flags allowed for MODE are:
-
- 'GCRY_MAC_FLAG_SECURE'
- Allocate all buffers and the resulting MAC in "secure memory".
- Use this if the MAC data is highly confidential.
-
- In order to use a handle for performing MAC algorithm operations, a
-'key' has to be set first:
-
- -- Function: gcry_error_t gcry_mac_setkey (gcry_mac_hd_t H, const void
- *KEY, size_t KEYLEN)
-
- Set the MAC key to the value of KEY of length KEYLEN bytes. With
- HMAC algorithms, there is no restriction on the length of the key.
- With CMAC algorithms, the length of the key is restricted to those
- supported by the underlying block cipher.
-
- GMAC algorithms and Poly1305-with-cipher algorithms need
-initialization vector to be set, which can be performed with function:
-
- -- Function: gcry_error_t gcry_mac_setiv (gcry_mac_hd_t H, const void
- *IV, size_t IVLEN)
-
- Set the IV to the value of IV of length IVLEN bytes.
-
- After you are done with the MAC calculation, you should release the
-resources by using:
-
- -- Function: void gcry_mac_close (gcry_mac_hd_t H)
-
- Release all resources of MAC context H. H should not be used after
- a call to this function. A 'NULL' passed as H is ignored. The
- function also clears all sensitive information associated with this
- handle.
-
- Often you have to do several MAC operations using the same algorithm.
-To avoid the overhead of creating and releasing context, a reset
-function is provided:
-
- -- Function: gcry_error_t gcry_mac_reset (gcry_mac_hd_t H)
-
- Reset the current context to its initial state. This is
- effectively identical to a close followed by an open and setting
- same key.
-
- Note that gcry_mac_reset is implemented as a macro.
-
- Now that we have prepared everything to calculate MAC, it is time to
-see how it is actually done.
-
- -- Function: gcry_error_t gcry_mac_write (gcry_mac_hd_t H, const void
- *BUFFER, size_t LENGTH)
-
- Pass LENGTH bytes of the data in BUFFER to the MAC object with
- handle H to update the MAC values. If this function is used after
- the context has been finalized, it will keep on pushing the data
- through the algorithm specific transform function and thereby
- change the context; however the results are not meaningful and this
- feature is only available to mitigate timing attacks.
-
- The way to read out the calculated MAC is by using the function:
-
- -- Function: gcry_error_t gcry_mac_read (gcry_mac_hd_t H, void *BUFFER,
- size_t *LENGTH)
-
- 'gcry_mac_read' returns the MAC after finalizing the calculation.
- Function copies the resulting MAC value to BUFFER of the length
- LENGTH. If LENGTH is larger than length of resulting MAC value,
- then length of MAC is returned through LENGTH.
-
- To compare existing MAC value with recalculated MAC, one is to use
-the function:
-
- -- Function: gcry_error_t gcry_mac_verify (gcry_mac_hd_t H, void
- *BUFFER, size_t LENGTH)
-
- 'gcry_mac_verify' finalizes MAC calculation and compares result
- with LENGTH bytes of data in BUFFER. Error code 'GPG_ERR_CHECKSUM'
- is returned if the MAC value in the buffer BUFFER does not match
- the MAC calculated in object H.
-
- In some situations it might be hard to remember the algorithm used
-for the MAC calculation. The following function might be used to get
-that information:
-
- -- Function: int gcry_mac_get_algo (gcry_mac_hd_t H)
-
- Retrieve the algorithm used with the handle H.
-
- MAC algorithms are identified by internal algorithm numbers (see
-'gcry_mac_open' for a list). However, in most applications they are
-used by names, so two functions are available to map between string
-representations and MAC algorithm identifiers.
-
- -- Function: const char * gcry_mac_algo_name (int ALGO)
-
- Map the MAC algorithm id ALGO to a string representation of the
- algorithm name. For unknown algorithms this function returns the
- string '"?"'. This function should not be used to test for the
- availability of an algorithm.
-
- -- Function: int gcry_mac_map_name (const char *NAME)
-
- Map the algorithm with NAME to a MAC algorithm identifier. Returns
- 0 if the algorithm name is not known. This function should not be
- used to test for the availability of an algorithm.
-
- To test whether an algorithm is actually available for use, the
-following macro should be used:
-
- -- Function: gcry_error_t gcry_mac_test_algo (int ALGO)
-
- The macro returns 0 if the MAC algorithm ALGO is available for use.
-
- If the length of a message digest is not known, it can be retrieved
-using the following function:
-
- -- Function: unsigned int gcry_mac_get_algo_maclen (int ALGO)
-
- Retrieve the length in bytes of the MAC yielded by algorithm ALGO.
- This is often used prior to 'gcry_mac_read' to allocate sufficient
- memory for the MAC value. On error '0' is returned.
-
- -- Function: unsigned int gcry_mac_get_algo_keylen (ALGO)
-
- This function returns length of the key for MAC algorithm ALGO. If
- the algorithm supports multiple key lengths, the default supported
- key length is returned. On error '0' is returned. The key length
- is returned as number of octets.
-
-\1f
-File: gcrypt.info, Node: Key Derivation, Next: Random Numbers, Prev: Message Authentication Codes, Up: Top
-
-9 Key Derivation
-****************
-
-Libgcypt provides a general purpose function to derive keys from
-strings.
-
- -- Function: gpg_error_t gcry_kdf_derive ( const void *PASSPHRASE,
- size_t PASSPHRASELEN, int ALGO, int SUBALGO, const void *SALT,
- size_t SALTLEN, unsigned long ITERATIONS, size_t KEYSIZE,
- void *KEYBUFFER )
-
- Derive a key from a passphrase. KEYSIZE gives the requested size
- of the keys in octets. KEYBUFFER is a caller provided buffer
- filled on success with the derived key. The input passphrase is
- taken from PASSPHRASE which is an arbitrary memory buffer of
- PASSPHRASELEN octets. ALGO specifies the KDF algorithm to use; see
- below. SUBALGO specifies an algorithm used internally by the KDF
- algorithms; this is usually a hash algorithm but certain KDF
- algorithms may use it differently. SALT is a salt of length
- SALTLEN octets, as needed by most KDF algorithms. ITERATIONS is a
- positive integer parameter to most KDFs.
-
- On success 0 is returned; on failure an error code.
-
- Currently supported KDFs (parameter ALGO):
-
- 'GCRY_KDF_SIMPLE_S2K'
- The OpenPGP simple S2K algorithm (cf. RFC4880). Its use is
- strongly deprecated. SALT and ITERATIONS are not needed and
- may be passed as 'NULL'/'0'.
-
- 'GCRY_KDF_SALTED_S2K'
- The OpenPGP salted S2K algorithm (cf. RFC4880). Usually not
- used. ITERATIONS is not needed and may be passed as '0'.
- SALTLEN must be given as 8.
-
- 'GCRY_KDF_ITERSALTED_S2K'
- The OpenPGP iterated+salted S2K algorithm (cf. RFC4880).
- This is the default for most OpenPGP applications. SALTLEN
- must be given as 8. Note that OpenPGP defines a special
- encoding of the ITERATIONS; however this function takes the
- plain decoded iteration count.
-
- 'GCRY_KDF_PBKDF2'
- The PKCS#5 Passphrase Based Key Derivation Function number 2.
-
- 'GCRY_KDF_SCRYPT'
- The SCRYPT Key Derivation Function. The subalgorithm is used
- to specify the CPU/memory cost parameter N, and the number of
- iterations is used for the parallelization parameter p. The
- block size is fixed at 8 in the current implementation.
-
-\1f
-File: gcrypt.info, Node: Random Numbers, Next: S-expressions, Prev: Key Derivation, Up: Top
-
-10 Random Numbers
-*****************
-
-* Menu:
-
-* Quality of random numbers:: Libgcrypt uses different quality levels.
-* Retrieving random numbers:: How to retrieve random numbers.
-
-\1f
-File: gcrypt.info, Node: Quality of random numbers, Next: Retrieving random numbers, Up: Random Numbers
-
-10.1 Quality of random numbers
-==============================
-
-Libgcypt offers random numbers of different quality levels:
-
- -- Data type: gcry_random_level_t
- The constants for the random quality levels are of this enum type.
-
-'GCRY_WEAK_RANDOM'
- For all functions, except for 'gcry_mpi_randomize', this level maps
- to GCRY_STRONG_RANDOM. If you do not want this, consider using
- 'gcry_create_nonce'.
-'GCRY_STRONG_RANDOM'
- Use this level for session keys and similar purposes.
-'GCRY_VERY_STRONG_RANDOM'
- Use this level for long term key material.
-
-\1f
-File: gcrypt.info, Node: Retrieving random numbers, Prev: Quality of random numbers, Up: Random Numbers
-
-10.2 Retrieving random numbers
-==============================
-
- -- Function: void gcry_randomize (unsigned char *BUFFER, size_t LENGTH,
- enum gcry_random_level LEVEL)
-
- Fill BUFFER with LENGTH random bytes using a random quality as
- defined by LEVEL.
-
- -- Function: void * gcry_random_bytes (size_t NBYTES, enum
- gcry_random_level LEVEL)
-
- Convenience function to allocate a memory block consisting of
- NBYTES fresh random bytes using a random quality as defined by
- LEVEL.
-
- -- Function: void * gcry_random_bytes_secure (size_t NBYTES, enum
- gcry_random_level LEVEL)
-
- Convenience function to allocate a memory block consisting of
- NBYTES fresh random bytes using a random quality as defined by
- LEVEL. This function differs from 'gcry_random_bytes' in that the
- returned buffer is allocated in a "secure" area of the memory.
-
- -- Function: void gcry_create_nonce (unsigned char *BUFFER, size_t
- LENGTH)
-
- Fill BUFFER with LENGTH unpredictable bytes. This is commonly
- called a nonce and may also be used for initialization vectors and
- padding. This is an extra function nearly independent of the other
- random function for 3 reasons: It better protects the regular
- random generator's internal state, provides better performance and
- does not drain the precious entropy pool.
-
-\1f
-File: gcrypt.info, Node: S-expressions, Next: MPI library, Prev: Random Numbers, Up: Top
-
-11 S-expressions
-****************
-
-S-expressions are used by the public key functions to pass complex data
-structures around. These LISP like objects are used by some
-cryptographic protocols (cf. RFC-2692) and Libgcrypt provides functions
-to parse and construct them. For detailed information, see 'Ron Rivest,
-code and description of S-expressions,
-<http://theory.lcs.mit.edu/~rivest/sexp.html>'.
-
-* Menu:
-
-* Data types for S-expressions:: Data types related with S-expressions.
-* Working with S-expressions:: How to work with S-expressions.
-
-\1f
-File: gcrypt.info, Node: Data types for S-expressions, Next: Working with S-expressions, Up: S-expressions
-
-11.1 Data types for S-expressions
-=================================
-
- -- Data type: gcry_sexp_t
- The 'gcry_sexp_t' type describes an object with the Libgcrypt
- internal representation of an S-expression.
-
-\1f
-File: gcrypt.info, Node: Working with S-expressions, Prev: Data types for S-expressions, Up: S-expressions
-
-11.2 Working with S-expressions
-===============================
-
-There are several functions to create an Libgcrypt S-expression object
-from its external representation or from a string template. There is
-also a function to convert the internal representation back into one of
-the external formats:
-
- -- Function: gcry_error_t gcry_sexp_new (gcry_sexp_t *R_SEXP,
- const void *BUFFER, size_t LENGTH, int AUTODETECT)
-
- This is the generic function to create an new S-expression object
- from its external representation in BUFFER of LENGTH bytes. On
- success the result is stored at the address given by R_SEXP. With
- AUTODETECT set to 0, the data in BUFFER is expected to be in
- canonized format, with AUTODETECT set to 1 the parses any of the
- defined external formats. If BUFFER does not hold a valid
- S-expression an error code is returned and R_SEXP set to 'NULL'.
- Note that the caller is responsible for releasing the newly
- allocated S-expression using 'gcry_sexp_release'.
-
- -- Function: gcry_error_t gcry_sexp_create (gcry_sexp_t *R_SEXP,
- void *BUFFER, size_t LENGTH, int AUTODETECT,
- void (*FREEFNC)(void*))
-
- This function is identical to 'gcry_sexp_new' but has an extra
- argument FREEFNC, which, when not set to 'NULL', is expected to be
- a function to release the BUFFER; most likely the standard 'free'
- function is used for this argument. This has the effect of
- transferring the ownership of BUFFER to the created object in
- R_SEXP. The advantage of using this function is that Libgcrypt
- might decide to directly use the provided buffer and thus avoid
- extra copying.
-
- -- Function: gcry_error_t gcry_sexp_sscan (gcry_sexp_t *R_SEXP,
- size_t *ERROFF, const char *BUFFER, size_t LENGTH)
-
- This is another variant of the above functions. It behaves nearly
- identical but provides an ERROFF argument which will receive the
- offset into the buffer where the parsing stopped on error.
-
- -- Function: gcry_error_t gcry_sexp_build (gcry_sexp_t *R_SEXP,
- size_t *ERROFF, const char *FORMAT, ...)
-
- This function creates an internal S-expression from the string
- template FORMAT and stores it at the address of R_SEXP. If there
- is a parsing error, the function returns an appropriate error code
- and stores the offset into FORMAT where the parsing stopped in
- ERROFF. The function supports a couple of printf-like formatting
- characters and expects arguments for some of these escape sequences
- right after FORMAT. The following format characters are defined:
-
- '%m'
- The next argument is expected to be of type 'gcry_mpi_t' and a
- copy of its value is inserted into the resulting S-expression.
- The MPI is stored as a signed integer.
- '%M'
- The next argument is expected to be of type 'gcry_mpi_t' and a
- copy of its value is inserted into the resulting S-expression.
- The MPI is stored as an unsigned integer.
- '%s'
- The next argument is expected to be of type 'char *' and that
- string is inserted into the resulting S-expression.
- '%d'
- The next argument is expected to be of type 'int' and its
- value is inserted into the resulting S-expression.
- '%u'
- The next argument is expected to be of type 'unsigned int' and
- its value is inserted into the resulting S-expression.
- '%b'
- The next argument is expected to be of type 'int' directly
- followed by an argument of type 'char *'. This represents a
- buffer of given length to be inserted into the resulting
- S-expression.
- '%S'
- The next argument is expected to be of type 'gcry_sexp_t' and
- a copy of that S-expression is embedded in the resulting
- S-expression. The argument needs to be a regular
- S-expression, starting with a parenthesis.
-
- No other format characters are defined and would return an error.
- Note that the format character '%%' does not exists, because a
- percent sign is not a valid character in an S-expression.
-
- -- Function: void gcry_sexp_release (gcry_sexp_t SEXP)
-
- Release the S-expression object SEXP. If the S-expression is
- stored in secure memory it explicitly zeroises that memory; note
- that this is done in addition to the zeroisation always done when
- freeing secure memory.
-
-The next 2 functions are used to convert the internal representation
-back into a regular external S-expression format and to show the
-structure for debugging.
-
- -- Function: size_t gcry_sexp_sprint (gcry_sexp_t SEXP, int MODE,
- char *BUFFER, size_t MAXLENGTH)
-
- Copies the S-expression object SEXP into BUFFER using the format
- specified in MODE. MAXLENGTH must be set to the allocated length
- of BUFFER. The function returns the actual length of valid bytes
- put into BUFFER or 0 if the provided buffer is too short. Passing
- 'NULL' for BUFFER returns the required length for BUFFER. For
- convenience reasons an extra byte with value 0 is appended to the
- buffer.
-
- The following formats are supported:
-
- 'GCRYSEXP_FMT_DEFAULT'
- Returns a convenient external S-expression representation.
-
- 'GCRYSEXP_FMT_CANON'
- Return the S-expression in canonical format.
-
- 'GCRYSEXP_FMT_BASE64'
- Not currently supported.
-
- 'GCRYSEXP_FMT_ADVANCED'
- Returns the S-expression in advanced format.
-
- -- Function: void gcry_sexp_dump (gcry_sexp_t SEXP)
-
- Dumps SEXP in a format suitable for debugging to Libgcrypt's
- logging stream.
-
-Often canonical encoding is used in the external representation. The
-following function can be used to check for valid encoding and to learn
-the length of the S-expression.
-
- -- Function: size_t gcry_sexp_canon_len (const unsigned char *BUFFER,
- size_t LENGTH, size_t *ERROFF, int *ERRCODE)
-
- Scan the canonical encoded BUFFER with implicit length values and
- return the actual length this S-expression uses. For a valid
- S-expression it should never return 0. If LENGTH is not 0, the
- maximum length to scan is given; this can be used for syntax checks
- of data passed from outside. ERRCODE and ERROFF may both be passed
- as 'NULL'.
-
-There are functions to parse S-expressions and retrieve elements:
-
- -- Function: gcry_sexp_t gcry_sexp_find_token (const gcry_sexp_t LIST,
- const char *TOKEN, size_t TOKLEN)
-
- Scan the S-expression for a sublist with a type (the car of the
- list) matching the string TOKEN. If TOKLEN is not 0, the token is
- assumed to be raw memory of this length. The function returns a
- newly allocated S-expression consisting of the found sublist or
- 'NULL' when not found.
-
- -- Function: int gcry_sexp_length (const gcry_sexp_t LIST)
-
- Return the length of the LIST. For a valid S-expression this
- should be at least 1.
-
- -- Function: gcry_sexp_t gcry_sexp_nth (const gcry_sexp_t LIST,
- int NUMBER)
-
- Create and return a new S-expression from the element with index
- NUMBER in LIST. Note that the first element has the index 0. If
- there is no such element, 'NULL' is returned.
-
- -- Function: gcry_sexp_t gcry_sexp_car (const gcry_sexp_t LIST)
-
- Create and return a new S-expression from the first element in
- LIST; this is called the "type" and should always exist per
- S-expression specification and in general be a string. 'NULL' is
- returned in case of a problem.
-
- -- Function: gcry_sexp_t gcry_sexp_cdr (const gcry_sexp_t LIST)
-
- Create and return a new list form all elements except for the first
- one. Note that this function may return an invalid S-expression
- because it is not guaranteed, that the type exists and is a string.
- However, for parsing a complex S-expression it might be useful for
- intermediate lists. Returns 'NULL' on error.
-
- -- Function: const char * gcry_sexp_nth_data (const gcry_sexp_t LIST,
- int NUMBER, size_t *DATALEN)
-
- This function is used to get data from a LIST. A pointer to the
- actual data with index NUMBER is returned and the length of this
- data will be stored to DATALEN. If there is no data at the given
- index or the index represents another list, 'NULL' is returned.
- *Caution:* The returned pointer is valid as long as LIST is not
- modified or released.
-
- Here is an example on how to extract and print the surname (Meier)
- from the S-expression '(Name Otto Meier (address Burgplatz 3))':
-
- size_t len;
- const char *name;
-
- name = gcry_sexp_nth_data (list, 2, &len);
- printf ("my name is %.*s\n", (int)len, name);
-
- -- Function: void * gcry_sexp_nth_buffer (const gcry_sexp_t LIST,
- int NUMBER, size_t *RLENGTH)
-
- This function is used to get data from a LIST. A malloced buffer
- with the actual data at list index NUMBER is returned and the
- length of this buffer will be stored to RLENGTH. If there is no
- data at the given index or the index represents another list,
- 'NULL' is returned. The caller must release the result using
- 'gcry_free'.
-
- Here is an example on how to extract and print the CRC value from
- the S-expression '(hash crc32 #23ed00d7)':
-
- size_t len;
- char *value;
-
- value = gcry_sexp_nth_buffer (list, 2, &len);
- if (value)
- fwrite (value, len, 1, stdout);
- gcry_free (value);
-
- -- Function: char * gcry_sexp_nth_string (gcry_sexp_t LIST, int NUMBER)
-
- This function is used to get and convert data from a LIST. The
- data is assumed to be a Nul terminated string. The caller must
- release this returned value using 'gcry_free'. If there is no data
- at the given index, the index represents a list or the value can't
- be converted to a string, 'NULL' is returned.
-
- -- Function: gcry_mpi_t gcry_sexp_nth_mpi (gcry_sexp_t LIST,
- int NUMBER, int MPIFMT)
-
- This function is used to get and convert data from a LIST. This
- data is assumed to be an MPI stored in the format described by
- MPIFMT and returned as a standard Libgcrypt MPI. The caller must
- release this returned value using 'gcry_mpi_release'. If there is
- no data at the given index, the index represents a list or the
- value can't be converted to an MPI, 'NULL' is returned. If you use
- this function to parse results of a public key function, you most
- likely want to use 'GCRYMPI_FMT_USG'.
-
- -- Function: gpg_error_t gcry_sexp_extract_param ( gcry_sexp_t SEXP,
- const char *PATH, const char *LIST, ...)
-
- Extract parameters from an S-expression using a list of parameter
- names. The names of these parameters are specified in LIST. White
- space between the parameter names are ignored. Some special
- characters may be given to control the conversion:
-
- '+'
- Switch to unsigned integer format (GCRYMPI_FMT_USG). This is
- the default mode.
- '-'
- Switch to standard signed format (GCRYMPI_FMT_STD).
- '/'
- Switch to opaque MPI format. The resulting MPIs may not be
- used for computations; see 'gcry_mpi_get_opaque' for details.
- '&'
- Switch to buffer descriptor mode. See below for details.
- '?'
- If immediately following a parameter letter (no white space
- allowed), that parameter is considered optional.
-
- In general parameter names are single letters. To use a string for
- a parameter name, enclose the name in single quotes.
-
- Unless in buffer descriptor mode for each parameter name a pointer
- to an 'gcry_mpi_t' variable is expected that must be set to 'NULL'
- prior to invoking this function, and finally a 'NULL' is expected.
- For example
-
- _gcry_sexp_extract_param (key, NULL, "n/x+e d-'foo'",
- &mpi_n, &mpi_x, &mpi_e, &mpi_foo, NULL)
-
- stores the parameter 'n' from KEY as an unsigned MPI into MPI_N,
- the parameter 'x' as an opaque MPI into MPI_X, the parameter 'e'
- again as an unsigned MPI into MPI_E, and the parameter 'foo' as a
- signed MPI.
-
- PATH is an optional string used to locate a token. The exclamation
- mark separated tokens are used via 'gcry_sexp_find_token' to find a
- start point inside the S-expression.
-
- In buffer descriptor mode a pointer to a 'gcry_buffer_t' descriptor
- is expected instead of a pointer to an MPI. The caller may use two
- different operation modes here: If the DATA field of the provided
- descriptor is 'NULL', the function allocates a new buffer and
- stores it at DATA; the other fields are set accordingly with OFF
- set to 0. If DATA is not 'NULL', the function assumes that the
- DATA, SIZE, and OFF fields specify a buffer where to but the value
- of the respective parameter; on return the LEN field receives the
- number of bytes copied to that buffer; in case the buffer is too
- small, the function immediately returns with an error code (and LEN
- is set to 0).
-
- The function returns 0 on success. On error an error code is
- returned, all passed MPIs that might have been allocated up to this
- point are deallocated and set to 'NULL', and all passed buffers are
- either truncated if the caller supplied the buffer, or deallocated
- if the function allocated the buffer.
-
-\1f
-File: gcrypt.info, Node: MPI library, Next: Prime numbers, Prev: S-expressions, Up: Top
-
-12 MPI library
-**************
-
-* Menu:
-
-* Data types:: MPI related data types.
-* Basic functions:: First steps with MPI numbers.
-* MPI formats:: External representation of MPIs.
-* Calculations:: Performing MPI calculations.
-* Comparisons:: How to compare MPI values.
-* Bit manipulations:: How to access single bits of MPI values.
-* EC functions:: Elliptic curve related functions.
-* Miscellaneous:: Miscellaneous MPI functions.
-
-Public key cryptography is based on mathematics with large numbers. To
-implement the public key functions, a library for handling these large
-numbers is required. Because of the general usefulness of such a
-library, its interface is exposed by Libgcrypt. In the context of
-Libgcrypt and in most other applications, these large numbers are called
-MPIs (multi-precision-integers).
-
-\1f
-File: gcrypt.info, Node: Data types, Next: Basic functions, Up: MPI library
-
-12.1 Data types
-===============
-
- -- Data type: gcry_mpi_t
- This type represents an object to hold an MPI.
-
- -- Data type: gcry_mpi_point_t
- This type represents an object to hold a point for elliptic curve
- math.
-
-\1f
-File: gcrypt.info, Node: Basic functions, Next: MPI formats, Prev: Data types, Up: MPI library
-
-12.2 Basic functions
-====================
-
-To work with MPIs, storage must be allocated and released for the
-numbers. This can be done with one of these functions:
-
- -- Function: gcry_mpi_t gcry_mpi_new (unsigned int NBITS)
-
- Allocate a new MPI object, initialize it to 0 and initially
- allocate enough memory for a number of at least NBITS. This
- pre-allocation is only a small performance issue and not actually
- necessary because Libgcrypt automatically re-allocates the required
- memory.
-
- -- Function: gcry_mpi_t gcry_mpi_snew (unsigned int NBITS)
-
- This is identical to 'gcry_mpi_new' but allocates the MPI in the so
- called "secure memory" which in turn will take care that all
- derived values will also be stored in this "secure memory". Use
- this for highly confidential data like private key parameters.
-
- -- Function: gcry_mpi_t gcry_mpi_copy (const gcry_mpi_t A)
-
- Create a new MPI as the exact copy of A but with the constant and
- immutable flags cleared.
-
- -- Function: void gcry_mpi_release (gcry_mpi_t A)
-
- Release the MPI A and free all associated resources. Passing
- 'NULL' is allowed and ignored. When a MPI stored in the "secure
- memory" is released, that memory gets wiped out immediately.
-
-The simplest operations are used to assign a new value to an MPI:
-
- -- Function: gcry_mpi_t gcry_mpi_set (gcry_mpi_t W, const gcry_mpi_t U)
-
- Assign the value of U to W and return W. If 'NULL' is passed for
- W, a new MPI is allocated, set to the value of U and returned.
-
- -- Function: gcry_mpi_t gcry_mpi_set_ui (gcry_mpi_t W, unsigned long U)
-
- Assign the value of U to W and return W. If 'NULL' is passed for
- W, a new MPI is allocated, set to the value of U and returned.
- This function takes an 'unsigned int' as type for U and thus it is
- only possible to set W to small values (usually up to the word size
- of the CPU).
-
- -- Function: void gcry_mpi_swap (gcry_mpi_t A, gcry_mpi_t B)
-
- Swap the values of A and B.
-
- -- Function: void gcry_mpi_snatch (gcry_mpi_t W, const gcry_mpi_t U)
-
- Set U into W and release U. If W is 'NULL' only U will be
- released.
-
- -- Function: void gcry_mpi_neg (gcry_mpi_t W, gcry_mpi_t U)
-
- Set the sign of W to the negative of U.
-
- -- Function: void gcry_mpi_abs (gcry_mpi_t W)
-
- Clear the sign of W.
-
-\1f
-File: gcrypt.info, Node: MPI formats, Next: Calculations, Prev: Basic functions, Up: MPI library
-
-12.3 MPI formats
-================
-
-The following functions are used to convert between an external
-representation of an MPI and the internal one of Libgcrypt.
-
- -- Function: gcry_error_t gcry_mpi_scan (gcry_mpi_t *R_MPI,
- enum gcry_mpi_format FORMAT, const unsigned char *BUFFER,
- size_t BUFLEN, size_t *NSCANNED)
-
- Convert the external representation of an integer stored in BUFFER
- with a length of BUFLEN into a newly created MPI returned which
- will be stored at the address of R_MPI. For certain formats the
- length argument is not required and should be passed as '0'. A
- BUFLEN larger than 16 MiByte will be rejected. After a successful
- operation the variable NSCANNED receives the number of bytes
- actually scanned unless NSCANNED was given as 'NULL'. FORMAT
- describes the format of the MPI as stored in BUFFER:
-
- 'GCRYMPI_FMT_STD'
- 2-complement stored without a length header. Note that
- 'gcry_mpi_print' stores a '0' as a string of zero length.
-
- 'GCRYMPI_FMT_PGP'
- As used by OpenPGP (only defined as unsigned). This is
- basically 'GCRYMPI_FMT_STD' with a 2 byte big endian length
- header. A length header indicating a length of more than
- 16384 is not allowed.
-
- 'GCRYMPI_FMT_SSH'
- As used in the Secure Shell protocol. This is
- 'GCRYMPI_FMT_STD' with a 4 byte big endian header.
-
- 'GCRYMPI_FMT_HEX'
- Stored as a string with each byte of the MPI encoded as 2 hex
- digits. Negative numbers are prefix with a minus sign and in
- addition the high bit is always zero to make clear that an
- explicit sign ist used. When using this format, BUFLEN must
- be zero.
-
- 'GCRYMPI_FMT_USG'
- Simple unsigned integer.
-
- Note that all of the above formats store the integer in big-endian
- format (MSB first).
-
- -- Function: gcry_error_t gcry_mpi_print (enum gcry_mpi_format FORMAT,
- unsigned char *BUFFER, size_t BUFLEN, size_t *NWRITTEN,
- const gcry_mpi_t A)
-
- Convert the MPI A into an external representation described by
- FORMAT (see above) and store it in the provided BUFFER which has a
- usable length of at least the BUFLEN bytes. If NWRITTEN is not
- NULL, it will receive the number of bytes actually stored in BUFFER
- after a successful operation.
-
- -- Function: gcry_error_t gcry_mpi_aprint (enum gcry_mpi_format FORMAT,
- unsigned char **BUFFER, size_t *NBYTES, const gcry_mpi_t A)
-
- Convert the MPI A into an external representation described by
- FORMAT (see above) and store it in a newly allocated buffer which
- address will be stored in the variable BUFFER points to. The
- number of bytes stored in this buffer will be stored in the
- variable NBYTES points to, unless NBYTES is 'NULL'.
-
- Even if NBYTES is zero, the function allocates at least one byte
- and store a zero there. Thus with formats 'GCRYMPI_FMT_STD' and
- 'GCRYMPI_FMT_USG' the caller may safely set a returned length of 0
- to 1 to represent a zero as a 1 byte string.
-
- -- Function: void gcry_mpi_dump (const gcry_mpi_t A)
-
- Dump the value of A in a format suitable for debugging to
- Libgcrypt's logging stream. Note that one leading space but no
- trailing space or linefeed will be printed. It is okay to pass
- 'NULL' for A.
-
-\1f
-File: gcrypt.info, Node: Calculations, Next: Comparisons, Prev: MPI formats, Up: MPI library
-
-12.4 Calculations
-=================
-
-Basic arithmetic operations:
-
- -- Function: void gcry_mpi_add (gcry_mpi_t W, gcry_mpi_t U,
- gcry_mpi_t V)
-
- W = U + V.
-
- -- Function: void gcry_mpi_add_ui (gcry_mpi_t W, gcry_mpi_t U,
- unsigned long V)
-
- W = U + V. Note that V is an unsigned integer.
-
- -- Function: void gcry_mpi_addm (gcry_mpi_t W, gcry_mpi_t U,
- gcry_mpi_t V, gcry_mpi_t M)
-
- W = U + V \bmod M.
-
- -- Function: void gcry_mpi_sub (gcry_mpi_t W, gcry_mpi_t U,
- gcry_mpi_t V)
-
- W = U - V.
-
- -- Function: void gcry_mpi_sub_ui (gcry_mpi_t W, gcry_mpi_t U,
- unsigned long V)
-
- W = U - V. V is an unsigned integer.
-
- -- Function: void gcry_mpi_subm (gcry_mpi_t W, gcry_mpi_t U,
- gcry_mpi_t V, gcry_mpi_t M)
-
- W = U - V \bmod M.
-
- -- Function: void gcry_mpi_mul (gcry_mpi_t W, gcry_mpi_t U,
- gcry_mpi_t V)
-
- W = U * V.
-
- -- Function: void gcry_mpi_mul_ui (gcry_mpi_t W, gcry_mpi_t U,
- unsigned long V)
-
- W = U * V. V is an unsigned integer.
-
- -- Function: void gcry_mpi_mulm (gcry_mpi_t W, gcry_mpi_t U,
- gcry_mpi_t V, gcry_mpi_t M)
-
- W = U * V \bmod M.
-
- -- Function: void gcry_mpi_mul_2exp (gcry_mpi_t W, gcry_mpi_t U,
- unsigned long E)
-
- W = U * 2^e.
-
- -- Function: void gcry_mpi_div (gcry_mpi_t Q, gcry_mpi_t R,
- gcry_mpi_t DIVIDEND, gcry_mpi_t DIVISOR, int ROUND)
-
- Q = DIVIDEND / DIVISOR, R = DIVIDEND \bmod DIVISOR. Q and R may be
- passed as 'NULL'. ROUND should be negative or 0.
-
- -- Function: void gcry_mpi_mod (gcry_mpi_t R, gcry_mpi_t DIVIDEND,
- gcry_mpi_t DIVISOR)
-
- R = DIVIDEND \bmod DIVISOR.
-
- -- Function: void gcry_mpi_powm (gcry_mpi_t W, const gcry_mpi_t B,
- const gcry_mpi_t E, const gcry_mpi_t M)
-
- W = B^e \bmod M.
-
- -- Function: int gcry_mpi_gcd (gcry_mpi_t G, gcry_mpi_t A,
- gcry_mpi_t B)
-
- Set G to the greatest common divisor of A and B. Return true if
- the G is 1.
-
- -- Function: int gcry_mpi_invm (gcry_mpi_t X, gcry_mpi_t A,
- gcry_mpi_t M)
-
- Set X to the multiplicative inverse of A \bmod M. Return true if
- the inverse exists.
-
-\1f
-File: gcrypt.info, Node: Comparisons, Next: Bit manipulations, Prev: Calculations, Up: MPI library
-
-12.5 Comparisons
-================
-
-The next 2 functions are used to compare MPIs:
-
- -- Function: int gcry_mpi_cmp (const gcry_mpi_t U, const gcry_mpi_t V)
-
- Compare the multi-precision-integers number U and V returning 0 for
- equality, a positive value for U > V and a negative for U < V. If
- both numbers are opaque values (cf, gcry_mpi_set_opaque) the
- comparison is done by checking the bit sizes using memcmp. If only
- one number is an opaque value, the opaque value is less than the
- other number.
-
- -- Function: int gcry_mpi_cmp_ui (const gcry_mpi_t U, unsigned long V)
-
- Compare the multi-precision-integers number U with the unsigned
- integer V returning 0 for equality, a positive value for U > V and
- a negative for U < V.
-
- -- Function: int gcry_mpi_is_neg (const gcry_mpi_t A)
-
- Return 1 if A is less than zero; return 0 if zero or positive.
-
-\1f
-File: gcrypt.info, Node: Bit manipulations, Next: EC functions, Prev: Comparisons, Up: MPI library
-
-12.6 Bit manipulations
-======================
-
-There are a couple of functions to get information on arbitrary bits in
-an MPI and to set or clear them:
-
- -- Function: unsigned int gcry_mpi_get_nbits (gcry_mpi_t A)
-
- Return the number of bits required to represent A.
-
- -- Function: int gcry_mpi_test_bit (gcry_mpi_t A, unsigned int N)
-
- Return true if bit number N (counting from 0) is set in A.
-
- -- Function: void gcry_mpi_set_bit (gcry_mpi_t A, unsigned int N)
-
- Set bit number N in A.
-
- -- Function: void gcry_mpi_clear_bit (gcry_mpi_t A, unsigned int N)
-
- Clear bit number N in A.
-
- -- Function: void gcry_mpi_set_highbit (gcry_mpi_t A, unsigned int N)
-
- Set bit number N in A and clear all bits greater than N.
-
- -- Function: void gcry_mpi_clear_highbit (gcry_mpi_t A, unsigned int N)
-
- Clear bit number N in A and all bits greater than N.
-
- -- Function: void gcry_mpi_rshift (gcry_mpi_t X, gcry_mpi_t A,
- unsigned int N)
-
- Shift the value of A by N bits to the right and store the result in
- X.
-
- -- Function: void gcry_mpi_lshift (gcry_mpi_t X, gcry_mpi_t A,
- unsigned int N)
-
- Shift the value of A by N bits to the left and store the result in
- X.
-
-\1f
-File: gcrypt.info, Node: EC functions, Next: Miscellaneous, Prev: Bit manipulations, Up: MPI library
-
-12.7 EC functions
-=================
-
-Libgcrypt provides an API to access low level functions used by its
-elliptic curve implementation. These functions allow to implement
-elliptic curve methods for which no explicit support is available.
-
- -- Function: gcry_mpi_point_t gcry_mpi_point_new (unsigned int NBITS)
-
- Allocate a new point object, initialize it to 0, and allocate
- enough memory for a points of at least NBITS. This pre-allocation
- yields only a small performance win and is not really necessary
- because Libgcrypt automatically re-allocates the required memory.
- Using 0 for NBITS is usually the right thing to do.
-
- -- Function: void gcry_mpi_point_release (gcry_mpi_point_t POINT)
-
- Release POINT and free all associated resources. Passing 'NULL' is
- allowed and ignored.
-
- -- Function: gcry_mpi_point_t gcry_mpi_point_copy
- (gcry_mpi_point_t POINT)
-
- Allocate and return a new point object and initialize it with
- POINT. If POINT is NULL the function is identical to
- 'gcry_mpi_point_new(0)'.
-
- -- Function: void gcry_mpi_point_get (gcry_mpi_t X, gcry_mpi_t Y,
- gcry_mpi_t Z, gcry_mpi_point_t POINT)
-
- Store the projective coordinates from POINT into the MPIs X, Y, and
- Z. If a coordinate is not required, 'NULL' may be used for X, Y,
- or Z.
-
- -- Function: void gcry_mpi_point_snatch_get (gcry_mpi_t X,
- gcry_mpi_t Y, gcry_mpi_t Z, gcry_mpi_point_t POINT)
-
- Store the projective coordinates from POINT into the MPIs X, Y, and
- Z. If a coordinate is not required, 'NULL' may be used for X, Y,
- or Z. The object POINT is then released. Using this function
- instead of 'gcry_mpi_point_get' and 'gcry_mpi_point_release' has
- the advantage of avoiding some extra memory allocations and copies.
-
- -- Function: gcry_mpi_point_t gcry_mpi_point_set (
- gcry_mpi_point_t POINT, gcry_mpi_t X, gcry_mpi_t Y,
- gcry_mpi_t Z)
-
- Store the projective coordinates from X, Y, and Z into POINT. If a
- coordinate is given as 'NULL', the value 0 is used. If 'NULL' is
- used for POINT a new point object is allocated and returned.
- Returns POINT or the newly allocated point object.
-
- -- Function: gcry_mpi_point_t gcry_mpi_point_snatch_set (
- gcry_mpi_point_t POINT, gcry_mpi_t X, gcry_mpi_t Y,
- gcry_mpi_t Z)
-
- Store the projective coordinates from X, Y, and Z into POINT. If a
- coordinate is given as 'NULL', the value 0 is used. If 'NULL' is
- used for POINT a new point object is allocated and returned. The
- MPIs X, Y, and Z are released. Using this function instead of
- 'gcry_mpi_point_set' and 3 calls to 'gcry_mpi_release' has the
- advantage of avoiding some extra memory allocations and copies.
- Returns POINT or the newly allocated point object.
-
- -- Function: gpg_error_t gcry_mpi_ec_new (gcry_ctx_t *R_CTX,
- gcry_sexp_t KEYPARAM, const char *CURVENAME)
-
- Allocate a new context for elliptic curve operations. If KEYPARAM
- is given it specifies the parameters of the curve (*note
- ecc_keyparam::). If CURVENAME is given in addition to KEYPARAM and
- the key parameters do not include a named curve reference, the
- string CURVENAME is used to fill in missing parameters. If only
- CURVENAME is given, the context is initialized for this named
- curve.
-
- If a parameter specifying a point (e.g. 'g' or 'q') is not found,
- the parser looks for a non-encoded point by appending '.x', '.y',
- and '.z' to the parameter name and looking them all up to create a
- point. A parameter with the suffix '.z' is optional and defaults
- to 1.
-
- On success the function returns 0 and stores the new context object
- at R_CTX; this object eventually needs to be released (*note
- gcry_ctx_release::). On error the function stores 'NULL' at R_CTX
- and returns an error code.
-
- -- Function: gcry_mpi_t gcry_mpi_ec_get_mpi ( const char *NAME,
- gcry_ctx_t CTX, int COPY)
-
- Return the MPI with NAME from the context CTX. If not found 'NULL'
- is returned. If the returned MPI may later be modified, it is
- suggested to pass '1' to COPY, so that the function guarantees that
- a modifiable copy of the MPI is returned. If '0' is used for COPY,
- this function may return a constant flagged MPI. In any case
- 'gcry_mpi_release' needs to be called to release the result. For
- valid names *note ecc_keyparam::. If the public key 'q' is
- requested but only the private key 'd' is available, 'q' will be
- recomputed on the fly. If a point parameter is requested it is
- returned as an uncompressed encoded point unless these special
- names are used:
- Q@EDDSA
- Return an EdDSA style compressed point. This is only
- supported for Twisted Edwards curves.
-
- -- Function: gcry_mpi_point_t gcry_mpi_ec_get_point ( const char *NAME,
- gcry_ctx_t CTX, int COPY)
-
- Return the point with NAME from the context CTX. If not found
- 'NULL' is returned. If the returned MPI may later be modified, it
- is suggested to pass '1' to COPY, so that the function guarantees
- that a modifiable copy of the MPI is returned. If '0' is used for
- COPY, this function may return a constant flagged point. In any
- case 'gcry_mpi_point_release' needs to be called to release the
- result. If the public key 'q' is requested but only the private
- key 'd' is available, 'q' will be recomputed on the fly.
-
- -- Function: gpg_error_t gcry_mpi_ec_set_mpi ( const char *NAME,
- gcry_mpi_t NEWVALUE, gcry_ctx_t CTX)
-
- Store the MPI NEWVALUE at NAME into the context CTX. On success
- '0' is returned; on error an error code. Valid names are the MPI
- parameters of an elliptic curve (*note ecc_keyparam::).
-
- -- Function: gpg_error_t gcry_mpi_ec_set_point ( const char *NAME,
- gcry_mpi_point_t NEWVALUE, gcry_ctx_t CTX)
-
- Store the point NEWVALUE at NAME into the context CTX. On success
- '0' is returned; on error an error code. Valid names are the point
- parameters of an elliptic curve (*note ecc_keyparam::).
-
- -- Function: gpg_err_code_t gcry_mpi_ec_decode_point (
- mpi_point_t RESULT, gcry_mpi_t VALUE, gcry_ctx_t CTX)
-
- Decode the point given as an MPI in VALUE and store at RESULT. To
- decide which encoding is used the function takes a context CTX
- which can be created with 'gcry_mpi_ec_new'. If 'NULL' is given
- for the context the function assumes a 0x04 prefixed uncompressed
- encoding. On error an error code is returned and RESULT might be
- changed.
-
- -- Function: int gcry_mpi_ec_get_affine ( gcry_mpi_t X, gcry_mpi_t Y,
- gcry_mpi_point_t POINT, gcry_ctx_t CTX)
-
- Compute the affine coordinates from the projective coordinates in
- POINT and store them into X and Y. If one coordinate is not
- required, 'NULL' may be passed to X or Y. CTX is the context
- object which has been created using 'gcry_mpi_ec_new'. Returns 0
- on success or not 0 if POINT is at infinity.
-
- Note that you can use 'gcry_mpi_ec_set_point' with the value
- 'GCRYMPI_CONST_ONE' for Z to convert affine coordinates back into
- projective coordinates.
-
- -- Function: void gcry_mpi_ec_dup ( gcry_mpi_point_t W,
- gcry_mpi_point_t U, gcry_ctx_t CTX)
-
- Double the point U of the elliptic curve described by CTX and store
- the result into W.
-
- -- Function: void gcry_mpi_ec_add ( gcry_mpi_point_t W,
- gcry_mpi_point_t U, gcry_mpi_point_t V, gcry_ctx_t CTX)
-
- Add the points U and V of the elliptic curve described by CTX and
- store the result into W.
-
- -- Function: void gcry_mpi_ec_sub ( gcry_mpi_point_t W,
- gcry_mpi_point_t U, gcry_mpi_point_t V, gcry_ctx_t CTX)
-
- Subtracts the point V from the point U of the elliptic curve
- described by CTX and store the result into W. Only Twisted Edwards
- curves are supported for now.
-
- -- Function: void gcry_mpi_ec_mul ( gcry_mpi_point_t W, gcry_mpi_t N,
- gcry_mpi_point_t U, gcry_ctx_t CTX)
-
- Multiply the point U of the elliptic curve described by CTX by N
- and store the result into W.
-
- -- Function: int gcry_mpi_ec_curve_point ( gcry_mpi_point_t POINT,
- gcry_ctx_t CTX)
-
- Return true if POINT is on the elliptic curve described by CTX.
-
-\1f
-File: gcrypt.info, Node: Miscellaneous, Prev: EC functions, Up: MPI library
-
-12.8 Miscellaneous
-==================
-
-An MPI data type is allowed to be "misused" to store an arbitrary value.
-Two functions implement this kludge:
-
- -- Function: gcry_mpi_t gcry_mpi_set_opaque (gcry_mpi_t A, void *P,
- unsigned int NBITS)
-
- Store NBITS of the value P points to in A and mark A as an opaque
- value (i.e. an value that can't be used for any math calculation
- and is only used to store an arbitrary bit pattern in A).
- Ownership of P is taken by this function and thus the user may not
- use dereference the passed value anymore. It is required that them
- memory referenced by P has been allocated in a way that 'gcry_free'
- is able to release it.
-
- WARNING: Never use an opaque MPI for actual math operations. The
- only valid functions are gcry_mpi_get_opaque and gcry_mpi_release.
- Use gcry_mpi_scan to convert a string of arbitrary bytes into an
- MPI.
-
- -- Function: gcry_mpi_t gcry_mpi_set_opaque_copy (gcry_mpi_t A,
- const void *P, unsigned int NBITS)
-
- Same as 'gcry_mpi_set_opaque' but ownership of P is not taken
- instead a copy of P is used.
-
- -- Function: void * gcry_mpi_get_opaque (gcry_mpi_t A,
- unsigned int *NBITS)
-
- Return a pointer to an opaque value stored in A and return its size
- in NBITS. Note that the returned pointer is still owned by A and
- that the function should never be used for an non-opaque MPI.
-
- Each MPI has an associated set of flags for special purposes. The
-currently defined flags are:
-
-'GCRYMPI_FLAG_SECURE'
- Setting this flag converts A into an MPI stored in "secure memory".
- Clearing this flag is not allowed.
-'GCRYMPI_FLAG_OPAQUE'
- This is an interanl flag, indicating the an opaque valuue and not
- an integer is stored. This is an read-only flag; it may not be set
- or cleared.
-'GCRYMPI_FLAG_IMMUTABLE'
- If this flag is set, the MPI is marked as immutable. Setting or
- changing the value of that MPI is ignored and an error message is
- logged. The flag is sometimes useful for debugging.
-'GCRYMPI_FLAG_CONST'
- If this flag is set, the MPI is marked as a constant and as
- immutable Setting or changing the value of that MPI is ignored and
- an error message is logged. Such an MPI will never be deallocated
- and may thus be used without copying. Note that using
- gcry_mpi_copy will return a copy of that constant with this and the
- immutable flag cleared. A few commonly used constants are
- pre-defined and accessible using the macros 'GCRYMPI_CONST_ONE',
- 'GCRYMPI_CONST_TWO', 'GCRYMPI_CONST_THREE', 'GCRYMPI_CONST_FOUR',
- and 'GCRYMPI_CONST_EIGHT'.
-'GCRYMPI_FLAG_USER1'
-'GCRYMPI_FLAG_USER2'
-'GCRYMPI_FLAG_USER3'
-'GCRYMPI_FLAG_USER4'
- These flags are reserved for use by the application.
-
- -- Function: void gcry_mpi_set_flag (gcry_mpi_t A,
- enum gcry_mpi_flag FLAG)
-
- Set the FLAG for the MPI A. The only allowed flags are
- 'GCRYMPI_FLAG_SECURE', 'GCRYMPI_FLAG_IMMUTABLE', and
- 'GCRYMPI_FLAG_CONST'.
-
- -- Function: void gcry_mpi_clear_flag (gcry_mpi_t A,
- enum gcry_mpi_flag FLAG)
-
- Clear FLAG for the multi-precision-integers A. The only allowed
- flag is 'GCRYMPI_FLAG_IMMUTABLE' but only if 'GCRYMPI_FLAG_CONST'
- is not set. If 'GCRYMPI_FLAG_CONST' is set, clearing
- 'GCRYMPI_FLAG_IMMUTABLE' will simply be ignored.
- o
- -- Function: int gcry_mpi_get_flag (gcry_mpi_t A,
- enum gcry_mpi_flag FLAG)
-
- Return true if FLAG is set for A.
-
- To put a random value into an MPI, the following convenience function
-may be used:
-
- -- Function: void gcry_mpi_randomize (gcry_mpi_t W, unsigned int NBITS,
- enum gcry_random_level LEVEL)
-
- Set the multi-precision-integers W to a random non-negative number
- of NBITS, using random data quality of level LEVEL. In case NBITS
- is not a multiple of a byte, NBITS is rounded up to the next byte
- boundary. When using a LEVEL of 'GCRY_WEAK_RANDOM' this function
- makes use of 'gcry_create_nonce'.
-
-\1f
-File: gcrypt.info, Node: Prime numbers, Next: Utilities, Prev: MPI library, Up: Top
-
-13 Prime numbers
-****************
-
-* Menu:
-
-* Generation:: Generation of new prime numbers.
-* Checking:: Checking if a given number is prime.
-
-\1f
-File: gcrypt.info, Node: Generation, Next: Checking, Up: Prime numbers
-
-13.1 Generation
-===============
-
- -- Function: gcry_error_t gcry_prime_generate (gcry_mpi_t
- *PRIME,unsigned int PRIME_BITS, unsigned int FACTOR_BITS,
- gcry_mpi_t **FACTORS, gcry_prime_check_func_t CB_FUNC, void
- *CB_ARG, gcry_random_level_t RANDOM_LEVEL, unsigned int FLAGS)
-
- Generate a new prime number of PRIME_BITS bits and store it in
- PRIME. If FACTOR_BITS is non-zero, one of the prime factors of
- (PRIME - 1) / 2 must be FACTOR_BITS bits long. If FACTORS is
- non-zero, allocate a new, 'NULL'-terminated array holding the prime
- factors and store it in FACTORS. FLAGS might be used to influence
- the prime number generation process.
-
- -- Function: gcry_error_t gcry_prime_group_generator (gcry_mpi_t *R_G,
- gcry_mpi_t PRIME, gcry_mpi_t *FACTORS, gcry_mpi_t START_G)
-
- Find a generator for PRIME where the factorization of (PRIME-1) is
- in the 'NULL' terminated array FACTORS. Return the generator as a
- newly allocated MPI in R_G. If START_G is not NULL, use this as
- the start for the search.
-
- -- Function: void gcry_prime_release_factors (gcry_mpi_t *FACTORS)
-
- Convenience function to release the FACTORS array.
-
-\1f
-File: gcrypt.info, Node: Checking, Prev: Generation, Up: Prime numbers
-
-13.2 Checking
-=============
-
- -- Function: gcry_error_t gcry_prime_check (gcry_mpi_t P, unsigned int
- FLAGS)
-
- Check whether the number P is prime. Returns zero in case P is
- indeed a prime, returns 'GPG_ERR_NO_PRIME' in case P is not a prime
- and a different error code in case something went horribly wrong.
-
-\1f
-File: gcrypt.info, Node: Utilities, Next: Tools, Prev: Prime numbers, Up: Top
-
-14 Utilities
-************
-
-* Menu:
-
-* Memory allocation:: Functions related with memory allocation.
-* Context management:: Functions related with context management.
-* Buffer description:: A data type to describe buffers.
-* Config reporting:: How to return Libgcrypt's configuration.
-
-\1f
-File: gcrypt.info, Node: Memory allocation, Next: Context management, Up: Utilities
-
-14.1 Memory allocation
-======================
-
- -- Function: void * gcry_malloc (size_t N)
-
- This function tries to allocate N bytes of memory. On success it
- returns a pointer to the memory area, in an out-of-core condition,
- it returns NULL.
-
- -- Function: void * gcry_malloc_secure (size_t N)
- Like 'gcry_malloc', but uses secure memory.
-
- -- Function: void * gcry_calloc (size_t N, size_t M)
-
- This function allocates a cleared block of memory (i.e.
- initialized with zero bytes) long enough to contain a vector of N
- elements, each of size M bytes. On success it returns a pointer to
- the memory block; in an out-of-core condition, it returns NULL.
-
- -- Function: void * gcry_calloc_secure (size_t N, size_t M)
- Like 'gcry_calloc', but uses secure memory.
-
- -- Function: void * gcry_realloc (void *P, size_t N)
-
- This function tries to resize the memory area pointed to by P to N
- bytes. On success it returns a pointer to the new memory area, in
- an out-of-core condition, it returns NULL. Depending on whether the
- memory pointed to by P is secure memory or not, gcry_realloc tries
- to use secure memory as well.
-
- -- Function: void gcry_free (void *P)
- Release the memory area pointed to by P.
-
-\1f
-File: gcrypt.info, Node: Context management, Next: Buffer description, Prev: Memory allocation, Up: Utilities
-
-14.2 Context management
-=======================
-
-Some function make use of a context object. As of now there are only a
-few math functions. However, future versions of Libgcrypt may make more
-use of this context object.
-
- -- Data type: gcry_ctx_t
- This type is used to refer to the general purpose context object.
-
- -- Function: void gcry_ctx_release (gcry_ctx_t CTX)
- Release the context object CTX and all associated resources. A
- 'NULL' passed as CTX is ignored.
-
-\1f
-File: gcrypt.info, Node: Buffer description, Next: Config reporting, Prev: Context management, Up: Utilities
-
-14.3 Buffer description
-=======================
-
-To help hashing non-contiguous areas of memory a general purpose data
-type is defined:
-
- -- Data type: gcry_buffer_t
- This type is a structure to describe a buffer. The user should
- make sure that this structure is initialized to zero. The
- available fields of this structure are:
-
- '.size'
- This is either 0 for no information available or indicates the
- allocated length of the buffer.
- '.off'
- This is the offset into the buffer.
- '.len'
- This is the valid length of the buffer starting at '.off'.
- '.data'
- This is the address of the buffer.
-
-\1f
-File: gcrypt.info, Node: Config reporting, Prev: Buffer description, Up: Utilities
-
-14.4 How to return Libgcrypt's configuration.
-=============================================
-
-Although 'GCRYCTL_PRINT_CONFIG' can be used to print configuration
-options, it is sometimes necessary to check them in a program. This can
-be accomplished by using this function:
-
- -- Function: char * gcry_get_config (int MODE, const char *WHAT)
-
- This function returns a malloced string with colon delimited
- configure options. With a value of 0 for MODE this string
- resembles the output of 'GCRYCTL_PRINT_CONFIG'. However, if WHAT
- is not NULL, only the line where the first field (e.g. "cpu-arch")
- matches WHAT is returned.
-
- Other values than 0 for MODE are not defined. The caller shall
- free the string using 'gcry_free'. On error NULL is returned and
- ERRNO is set; if a value for WHAT is unknow ERRNO will be set to 0.
-
-\1f
-File: gcrypt.info, Node: Tools, Next: Configuration, Prev: Utilities, Up: Top
-
-15 Tools
-********
-
-* Menu:
-
-* hmac256:: A standalone HMAC-SHA-256 implementation
-
-\1f
-File: gcrypt.info, Node: hmac256, Up: Tools
-
-15.1 A HMAC-SHA-256 tool
-========================
-
-This is a standalone HMAC-SHA-256 implementation used to compute an
-HMAC-SHA-256 message authentication code. The tool has originally been
-developed as a second implementation for Libgcrypt to allow comparing
-against the primary implementation and to be used for internal
-consistency checks. It should not be used for sensitive data because no
-mechanisms to clear the stack etc are used.
-
- The code has been written in a highly portable manner and requires
-only a few standard definitions to be provided in a config.h file.
-
-'hmac256' is commonly invoked as
-
- hmac256 "This is my key" foo.txt
-
-This compute the MAC on the file 'foo.txt' using the key given on the
-command line.
-
-'hmac256' understands these options:
-
-'--binary'
- Print the MAC as a binary string. The default is to print the MAC
- encoded has lower case hex digits.
-
-'--version'
- Print version of the program and exit.
-
-\1f
-File: gcrypt.info, Node: Configuration, Next: Architecture, Prev: Tools, Up: Top
-
-16 Configuration files and environment variables
-************************************************
-
-This chapter describes which files and environment variables can be used
-to change the behaviour of Libgcrypt.
-
-The environment variables considered by Libgcrypt are:
-
-'GCRYPT_BARRETT'
- By setting this variable to any value a different algorithm for
- modular reduction is used for ECC.
-
-'GCRYPT_RNDUNIX_DBG'
-'GCRYPT_RNDUNIX_DBGALL'
- These two environment variables are used to enable debug output for
- the rndunix entropy gatherer, which is used on systems lacking a
- /dev/random device. The value of 'GCRYPT_RNDUNIX_DBG' is a file
- name or '-' for stdout. Debug output is the written to this file.
- By setting 'GCRYPT_RNDUNIX_DBGALL' to any value the debug output
- will be more verbose.
-
-'GCRYPT_RNDW32_NOPERF'
- Setting this environment variable on Windows to any value disables
- the use of performance data ('HKEY_PERFORMANCE_DATA') as source for
- entropy. On some older Windows systems this could help to speed up
- the creation of random numbers but also decreases the amount of
- data used to init the random number generator.
-
-'GCRYPT_RNDW32_DBG'
- Setting the value of this variable to a positive integer logs
- information about the Windows entropy gatherer using the standard
- log interface.
-
-'HOME'
- This is used to locate the socket to connect to the EGD random
- daemon. The EGD can be used on system without a /dev/random to
- speed up the random number generator. It is not needed on the
- majority of today's operating systems and support for EGD requires
- the use of a configure option at build time.
-
-The files which Libgcrypt uses to retrieve system information and the
-files which can be created by the user to modify Libgcrypt's behavior
-are:
-
-'/etc/gcrypt/hwf.deny'
- This file can be used to disable the use of hardware based
- optimizations, *note hardware features::.
-
-'/etc/gcrypt/random.conf'
- This file can be used to globally change parameters of the random
- generator. The file is a simple text file where empty lines and
- lines with the first non white-space character being '#' are
- ignored. Supported options are
-
- 'disable-jent'
- Disable the use of the jitter based entropy generator.
-
- 'only-urandom'
- Always use the non-blocking /dev/urandom or the respective
- system call instead of the blocking /dev/random. If Libgcrypt
- is used early in the boot process of the system, this option
- should only be used if the system also supports the getrandom
- system call.
-
-'/etc/gcrypt/fips_enabled'
-'/proc/sys/crypto/fips_enabled'
- On Linux these files are used to enable FIPS mode, *note enabling
- fips mode::.
-
-'/proc/cpuinfo'
-'/proc/self/auxv'
- On Linux running on the ARM architecture, these files are used to
- read hardware capabilities of the CPU.
-
-\1f
-File: gcrypt.info, Node: Architecture, Next: Self-Tests, Prev: Configuration, Up: Top
-
-17 Architecture
-***************
-
-This chapter describes the internal architecture of Libgcrypt.
-
- Libgcrypt is a function library written in ISO C-90. Any compliant
-compiler should be able to build Libgcrypt as long as the target is
-either a POSIX platform or compatible to the API used by Windows NT.
-Provisions have been take so that the library can be directly used from
-C++ applications; however building with a C++ compiler is not supported.
-
- Building Libgcrypt is done by using the common './configure && make'
-approach. The configure command is included in the source distribution
-and as a portable shell script it works on any Unix-alike system. The
-result of running the configure script are a C header file ('config.h'),
-customized Makefiles, the setup of symbolic links and a few other
-things. After that the make tool builds and optionally installs the
-library and the documentation. See the files 'INSTALL' and 'README' in
-the source distribution on how to do this.
-
- Libgcrypt is developed using a Subversion(1) repository. Although
-all released versions are tagged in this repository, they should not be
-used to build production versions of Libgcrypt. Instead released
-tarballs should be used. These tarballs are available from several
-places with the master copy at 'ftp://ftp.gnupg.org/gcrypt/libgcrypt/'.
-Announcements of new releases are posted to the
-'gnupg-announce@gnupg.org' mailing list(2).
-
- \0\b[image src="libgcrypt-modules.png" alt="Libgcrypt subsystems"\0\b]
-
-Figure 17.1: Libgcrypt subsystems
-
- Libgcrypt consists of several subsystems (*note Figure 17.1:
-fig:subsystems.) and all these subsystems provide a public API; this
-includes the helper subsystems like the one for S-expressions. The API
-style depends on the subsystem; in general an open-use-close approach is
-implemented. The open returns a handle to a context used for all
-further operations on this handle, several functions may then be used on
-this handle and a final close function releases all resources associated
-with the handle.
-
-* Menu:
-
-* Public-Key Subsystem Architecture:: About public keys.
-* Symmetric Encryption Subsystem Architecture:: About standard ciphers.
-* Hashing and MACing Subsystem Architecture:: About hashing.
-* Multi-Precision-Integer Subsystem Architecture:: About big integers.
-* Prime-Number-Generator Subsystem Architecture:: About prime numbers.
-* Random-Number Subsystem Architecture:: About random stuff.
-
- ---------- Footnotes ----------
-
- (1) A version control system available for many platforms
-
- (2) See <http://www.gnupg.org/documentation/mailing-lists.en.html>
-for details.
-
-\1f
-File: gcrypt.info, Node: Public-Key Subsystem Architecture, Next: Symmetric Encryption Subsystem Architecture, Up: Architecture
-
-17.1 Public-Key Architecture
-============================
-
-Because public key cryptography is almost always used to process small
-amounts of data (hash values or session keys), the interface is not
-implemented using the open-use-close paradigm, but with single
-self-contained functions. Due to the wide variety of parameters
-required by different algorithms S-expressions, as flexible way to
-convey these parameters, are used. There is a set of helper functions
-to work with these S-expressions.
-
- Aside of functions to register new algorithms, map algorithms names
-to algorithms identifiers and to lookup properties of a key, the
-following main functions are available:
-
-'gcry_pk_encrypt'
- Encrypt data using a public key.
-
-'gcry_pk_decrypt'
- Decrypt data using a private key.
-
-'gcry_pk_sign'
- Sign data using a private key.
-
-'gcry_pk_verify'
- Verify that a signature matches the data.
-
-'gcry_pk_testkey'
- Perform a consistency over a public or private key.
-
-'gcry_pk_genkey'
- Create a new public/private key pair.
-
- All these functions lookup the module implementing the algorithm and
-pass the actual work to that module. The parsing of the S-expression
-input and the construction of S-expression for the return values is done
-by the high level code ('cipher/pubkey.c'). Thus the internal interface
-between the algorithm modules and the high level functions passes data
-in a custom format.
-
- By default Libgcrypt uses a blinding technique for RSA decryption to
-mitigate real world timing attacks over a network: Instead of using the
-RSA decryption directly, a blinded value y = x r^{e} \bmod n is
-decrypted and the unblinded value x' = y' r^{-1} \bmod n returned. The
-blinding value r is a random value with the size of the modulus n and
-generated with 'GCRY_WEAK_RANDOM' random level.
-
- The algorithm used for RSA and DSA key generation depends on whether
-Libgcrypt is operated in standard or in FIPS mode. In standard mode an
-algorithm based on the Lim-Lee prime number generator is used. In FIPS
-mode RSA keys are generated as specified in ANSI X9.31 (1998) and DSA
-keys as specified in FIPS 186-2.
-
-\1f
-File: gcrypt.info, Node: Symmetric Encryption Subsystem Architecture, Next: Hashing and MACing Subsystem Architecture, Prev: Public-Key Subsystem Architecture, Up: Architecture
-
-17.2 Symmetric Encryption Subsystem Architecture
-================================================
-
-The interface to work with symmetric encryption algorithms is made up of
-functions from the 'gcry_cipher_' name space. The implementation
-follows the open-use-close paradigm and uses registered algorithm
-modules for the actual work. Unless a module implements optimized
-cipher mode implementations, the high level code ('cipher/cipher.c')
-implements the modes and calls the core algorithm functions to process
-each block.
-
- The most important functions are:
-
-'gcry_cipher_open'
- Create a new instance to encrypt or decrypt using a specified
- algorithm and mode.
-
-'gcry_cipher_close'
- Release an instance.
-
-'gcry_cipher_setkey'
- Set a key to be used for encryption or decryption.
-
-'gcry_cipher_setiv'
- Set an initialization vector to be used for encryption or
- decryption.
-
-'gcry_cipher_encrypt'
-'gcry_cipher_decrypt'
- Encrypt or decrypt data. These functions may be called with
- arbitrary amounts of data and as often as needed to encrypt or
- decrypt all data.
-
- There are also functions to query properties of algorithms or
-context, like block length, key length, map names or to enable features
-like padding methods.
-
-\1f
-File: gcrypt.info, Node: Hashing and MACing Subsystem Architecture, Next: Multi-Precision-Integer Subsystem Architecture, Prev: Symmetric Encryption Subsystem Architecture, Up: Architecture
-
-17.3 Hashing and MACing Subsystem Architecture
-==============================================
-
-The interface to work with message digests and CRC algorithms is made up
-of functions from the 'gcry_md_' name space. The implementation follows
-the open-use-close paradigm and uses registered algorithm modules for
-the actual work. Although CRC algorithms are not considered
-cryptographic hash algorithms, they share enough properties so that it
-makes sense to handle them in the same way. It is possible to use
-several algorithms at once with one context and thus compute them all on
-the same data.
-
- The most important functions are:
-
-'gcry_md_open'
- Create a new message digest instance and optionally enable one
- algorithm. A flag may be used to turn the message digest algorithm
- into a HMAC algorithm.
-
-'gcry_md_enable'
- Enable an additional algorithm for the instance.
-
-'gcry_md_setkey'
- Set the key for the MAC.
-
-'gcry_md_write'
- Pass more data for computing the message digest to an instance.
-
-'gcry_md_putc'
- Buffered version of 'gcry_md_write' implemented as a macro.
-
-'gcry_md_read'
- Finalize the computation of the message digest or HMAC and return
- the result.
-
-'gcry_md_close'
- Release an instance
-
-'gcry_md_hash_buffer'
- Convenience function to directly compute a message digest over a
- memory buffer without the need to create an instance first.
-
- There are also functions to query properties of algorithms or the
-instance, like enabled algorithms, digest length, map algorithm names.
-it is also possible to reset an instance or to copy the current state of
-an instance at any time. Debug functions to write the hashed data to
-files are available as well.
-
-\1f
-File: gcrypt.info, Node: Multi-Precision-Integer Subsystem Architecture, Next: Prime-Number-Generator Subsystem Architecture, Prev: Hashing and MACing Subsystem Architecture, Up: Architecture
-
-17.4 Multi-Precision-Integer Subsystem Architecture
-===================================================
-
-The implementation of Libgcrypt's big integer computation code is based
-on an old release of GNU Multi-Precision Library (GMP). The decision not
-to use the GMP library directly was due to stalled development at that
-time and due to security requirements which could not be provided by the
-code in GMP. As GMP does, Libgcrypt provides high performance assembler
-implementations of low level code for several CPUS to gain much better
-performance than with a generic C implementation.
-
-Major features of Libgcrypt's multi-precision-integer code compared to
-GMP are:
-
- * Avoidance of stack based allocations to allow protection against
- swapping out of sensitive data and for easy zeroing of sensitive
- intermediate results.
-
- * Optional use of secure memory and tracking of its use so that
- results are also put into secure memory.
-
- * MPIs are identified by a handle (implemented as a pointer) to give
- better control over allocations and to augment them with extra
- properties like opaque data.
-
- * Removal of unnecessary code to reduce complexity.
-
- * Functions specialized for public key cryptography.
-
-\1f
-File: gcrypt.info, Node: Prime-Number-Generator Subsystem Architecture, Next: Random-Number Subsystem Architecture, Prev: Multi-Precision-Integer Subsystem Architecture, Up: Architecture
-
-17.5 Prime-Number-Generator Subsystem Architecture
-==================================================
-
-Libgcrypt provides an interface to its prime number generator. These
-functions make use of the internal prime number generator which is
-required for the generation for public key key pairs. The plain prime
-checking function is exported as well.
-
- The generation of random prime numbers is based on the Lim and Lee
-algorithm to create practically save primes.(1) This algorithm creates
-a pool of smaller primes, select a few of them to create candidate
-primes of the form 2 * p_0 * p_1 * ... * p_n + 1, tests the candidate
-for primality and permutates the pool until a prime has been found. It
-is possible to clamp one of the small primes to a certain size to help
-DSA style algorithms. Because most of the small primes in the pool are
-not used for the resulting prime number, they are saved for later use
-(see 'save_pool_prime' and 'get_pool_prime' in 'cipher/primegen.c').
-The prime generator optionally supports the finding of an appropriate
-generator.
-
-The primality test works in three steps:
-
- 1. The standard sieve algorithm using the primes up to 4999 is used as
- a quick first check.
-
- 2. A Fermat test filters out almost all non-primes.
-
- 3. A 5 round Rabin-Miller test is finally used. The first round uses
- a witness of 2, whereas the next rounds use a random witness.
-
- To support the generation of RSA and DSA keys in FIPS mode according
-to X9.31 and FIPS 186-2, Libgcrypt implements two additional prime
-generation functions: '_gcry_derive_x931_prime' and
-'_gcry_generate_fips186_2_prime'. These functions are internal and not
-available through the public API.
-
- ---------- Footnotes ----------
-
- (1) Chae Hoon Lim and Pil Joong Lee. A key recovery attack on
-discrete log-based schemes using a prime order subgroup. In Burton S.
-Kaliski Jr., editor, Advances in Cryptology: Crypto '97, pages 249-263,
-Berlin / Heidelberg / New York, 1997. Springer-Verlag. Described on
-page 260.
-
-\1f
-File: gcrypt.info, Node: Random-Number Subsystem Architecture, Prev: Prime-Number-Generator Subsystem Architecture, Up: Architecture
-
-17.6 Random-Number Subsystem Architecture
-=========================================
-
-Libgcrypt provides 3 levels or random quality: The level
-'GCRY_VERY_STRONG_RANDOM' usually used for key generation, the level
-'GCRY_STRONG_RANDOM' for all other strong random requirements and the
-function 'gcry_create_nonce' which is used for weaker usages like
-nonces. There is also a level 'GCRY_WEAK_RANDOM' which in general maps
-to 'GCRY_STRONG_RANDOM' except when used with the function
-'gcry_mpi_randomize', where it randomizes an multi-precision-integer
-using the 'gcry_create_nonce' function.
-
-There are two distinct random generators available:
-
- * The Continuously Seeded Pseudo Random Number Generator (CSPRNG),
- which is based on the classic GnuPG derived big pool
- implementation. Implemented in 'random/random-csprng.c' and used
- by default.
- * A FIPS approved ANSI X9.31 PRNG using AES with a 128 bit key.
- Implemented in 'random/random-fips.c' and used if Libgcrypt is in
- FIPS mode.
-
-Both generators make use of so-called entropy gathering modules:
-
-rndlinux
- Uses the operating system provided '/dev/random' and '/dev/urandom'
- devices. The '/dev/gcrypt/random.conf' config option
- 'only-urandom' can be used to inhibit the use of the blocking
- '/dev/random' device.
-
-rndunix
- Runs several operating system commands to collect entropy from
- sources like virtual machine and process statistics. It is a kind
- of poor-man's '/dev/random' implementation. It is not available in
- FIPS mode.
-
-rndegd
- Uses the operating system provided Entropy Gathering Daemon (EGD).
- The EGD basically uses the same algorithms as rndunix does.
- However as a system daemon it keeps on running and thus can serve
- several processes requiring entropy input and does not waste
- collected entropy if the application does not need all the
- collected entropy. It is not available in FIPS mode.
-
-rndw32
- Targeted for the Microsoft Windows OS. It uses certain properties
- of that system and is the only gathering module available for that
- OS.
-
-rndhw
- Extra module to collect additional entropy by utilizing a hardware
- random number generator. As of now the supported hardware RNG is
- the Padlock engine of VIA (Centaur) CPUs and x86 CPUs with the
- RDRAND instruction. It is not available in FIPS mode.
-
-rndjent
- Extra module to collect additional entropy using a CPU jitter based
- approach. This is only used on X86 hardware where the RDTSC opcode
- is available. The '/dev/gcrypt/random.conf' config option
- 'disable-jent' can be used to inhibit the use of this module.
-
-* Menu:
-
-* CSPRNG Description:: Description of the CSPRNG.
-* FIPS PRNG Description:: Description of the FIPS X9.31 PRNG.
-
-\1f
-File: gcrypt.info, Node: CSPRNG Description, Next: FIPS PRNG Description, Up: Random-Number Subsystem Architecture
-
-17.6.1 Description of the CSPRNG
---------------------------------
-
-This random number generator is loosely modelled after the one described
-in Peter Gutmann's paper: "Software Generation of Practically Strong
-Random Numbers".(1)
-
- A pool of 600 bytes is used and mixed using the core SHA-1 hash
-transform function. Several extra features are used to make the robust
-against a wide variety of attacks and to protect against failures of
-subsystems. The state of the generator may be saved to a file and
-initially seed form a file.
-
- Depending on how Libgcrypt was build the generator is able to select
-the best working entropy gathering module. It makes use of the slow and
-fast collection methods and requires the pool to initially seeded form
-the slow gatherer or a seed file. An entropy estimation is used to mix
-in enough data from the gather modules before returning the actual
-random output. Process fork detection and protection is implemented.
-
- The implementation of the nonce generator (for 'gcry_create_nonce')
-is a straightforward repeated hash design: A 28 byte buffer is initially
-seeded with the PID and the time in seconds in the first 20 bytes and
-with 8 bytes of random taken from the 'GCRY_STRONG_RANDOM' generator.
-Random numbers are then created by hashing all the 28 bytes with SHA-1
-and saving that again in the first 20 bytes. The hash is also returned
-as result.
-
- ---------- Footnotes ----------
-
- (1) Also described in chapter 6 of his book "Cryptographic Security
-Architecture", New York, 2004, ISBN 0-387-95387-6.
-
-\1f
-File: gcrypt.info, Node: FIPS PRNG Description, Prev: CSPRNG Description, Up: Random-Number Subsystem Architecture
-
-17.6.2 Description of the FIPS X9.31 PRNG
------------------------------------------
-
-The core of this deterministic random number generator is implemented
-according to the document "NIST-Recommended Random Number Generator
-Based on ANSI X9.31 Appendix A.2.4 Using the 3-Key Triple DES and AES
-Algorithms", dated 2005-01-31. This implementation uses the AES
-variant.
-
- The generator is based on contexts to utilize the same core functions
-for all random levels as required by the high-level interface. All
-random generators return their data in 128 bit blocks. If the caller
-requests less bits, the extra bits are not used. The key for each
-generator is only set once at the first time a generator context is
-used. The seed value is set along with the key and again after 1000
-output blocks.
-
- On Unix like systems the 'GCRY_VERY_STRONG_RANDOM' and
-'GCRY_STRONG_RANDOM' generators are keyed and seeded using the rndlinux
-module with the '/dev/random' device. Thus these generators may block
-until the OS kernel has collected enough entropy. When used with
-Microsoft Windows the rndw32 module is used instead.
-
- The generator used for 'gcry_create_nonce' is keyed and seeded from
-the 'GCRY_STRONG_RANDOM' generator. Thus is may also block if the
-'GCRY_STRONG_RANDOM' generator has not yet been used before and thus
-gets initialized on the first use by 'gcry_create_nonce'. This special
-treatment is justified by the weaker requirements for a nonce generator
-and to save precious kernel entropy for use by the "real" random
-generators.
-
- A self-test facility uses a separate context to check the
-functionality of the core X9.31 functions using a known answers test.
-During runtime each output block is compared to the previous one to
-detect a stuck generator.
-
- The DT value for the generator is made up of the current time down to
-microseconds (if available) and a free running 64 bit counter. When
-used with the test context the DT value is taken from the context and
-incremented on each use.
-
-\1f
-File: gcrypt.info, Node: Self-Tests, Next: FIPS Mode, Prev: Architecture, Up: Top
-
-Appendix A Description of the Self-Tests
-****************************************
-
-In addition to the build time regression test suite, Libgcrypt
-implements self-tests to be performed at runtime. Which self-tests are
-actually used depends on the mode Libgcrypt is used in. In standard
-mode a limited set of self-tests is run at the time an algorithm is
-first used. Note that not all algorithms feature a self-test in
-standard mode. The 'GCRYCTL_SELFTEST' control command may be used to
-run all implemented self-tests at any time; this will even run more
-tests than those run in FIPS mode.
-
- If any of the self-tests fails, the library immediately returns an
-error code to the caller. If Libgcrypt is in FIPS mode the self-tests
-will be performed within the "Self-Test" state and any failure puts the
-library into the "Error" state.
-
-A.1 Power-Up Tests
-==================
-
-Power-up tests are only performed if Libgcrypt is in FIPS mode.
-
-A.1.1 Symmetric Cipher Algorithm Power-Up Tests
------------------------------------------------
-
-The following symmetric encryption algorithm tests are run during
-power-up:
-
-3DES
- To test the 3DES 3-key EDE encryption in ECB mode these tests are
- run:
- 1. A known answer test is run on a 64 bit test vector processed
- by 64 rounds of Single-DES block encryption and decryption
- using a key changed with each round.
- 2. A known answer test is run on a 64 bit test vector processed
- by 16 rounds of 2-key and 3-key Triple-DES block encryption
- and decryptions using a key changed with each round.
- 3. 10 known answer tests using 3-key Triple-DES EDE encryption,
- comparing the ciphertext to the known value, then running a
- decryption and comparing it to the initial plaintext.
- ('cipher/des.c:selftest')
-
-AES-128
- A known answer tests is run using one test vector and one test key
- with AES in ECB mode. ('cipher/rijndael.c:selftest_basic_128')
-
-AES-192
- A known answer tests is run using one test vector and one test key
- with AES in ECB mode. ('cipher/rijndael.c:selftest_basic_192')
-
-AES-256
- A known answer tests is run using one test vector and one test key
- with AES in ECB mode. ('cipher/rijndael.c:selftest_basic_256')
-
-A.1.2 Hash Algorithm Power-Up Tests
------------------------------------
-
-The following hash algorithm tests are run during power-up:
-
-SHA-1
- A known answer test using the string '"abc"' is run.
- ('cipher/sha1.c:selftests_sha1')
-SHA-224
- A known answer test using the string '"abc"' is run.
- ('cipher/sha256.c:selftests_sha224')
-SHA-256
- A known answer test using the string '"abc"' is run.
- ('cipher/sha256.c:selftests_sha256')
-SHA-384
- A known answer test using the string '"abc"' is run.
- ('cipher/sha512.c:selftests_sha384')
-SHA-512
- A known answer test using the string '"abc"' is run.
- ('cipher/sha512.c:selftests_sha512')
-
-A.1.3 MAC Algorithm Power-Up Tests
-----------------------------------
-
-The following MAC algorithm tests are run during power-up:
-
-HMAC SHA-1
- A known answer test using 9 byte of data and a 64 byte key is run.
- ('cipher/hmac-tests.c:selftests_sha1')
-HMAC SHA-224
- A known answer test using 28 byte of data and a 4 byte key is run.
- ('cipher/hmac-tests.c:selftests_sha224')
-HMAC SHA-256
- A known answer test using 28 byte of data and a 4 byte key is run.
- ('cipher/hmac-tests.c:selftests_sha256')
-HMAC SHA-384
- A known answer test using 28 byte of data and a 4 byte key is run.
- ('cipher/hmac-tests.c:selftests_sha384')
-HMAC SHA-512
- A known answer test using 28 byte of data and a 4 byte key is run.
- ('cipher/hmac-tests.c:selftests_sha512')
-
-A.1.4 Random Number Power-Up Test
----------------------------------
-
-The DRNG is tested during power-up this way:
-
- 1. Requesting one block of random using the public interface to check
- general working and the duplicated block detection.
- 2. 3 know answer tests using pre-defined keys, seed and initial DT
- values. For each test 3 blocks of 16 bytes are requested and
- compared to the expected result. The DT value is incremented for
- each block.
-
-A.1.5 Public Key Algorithm Power-Up Tests
------------------------------------------
-
-The public key algorithms are tested during power-up:
-
-RSA
- A pre-defined 1024 bit RSA key is used and these tests are run in
- turn:
- 1. Conversion of S-expression to internal format.
- ('cipher/rsa.c:selftests_rsa')
- 2. Private key consistency check. ('cipher/rsa.c:selftests_rsa')
- 3. A pre-defined 20 byte value is signed with PKCS#1 padding for
- SHA-1. The result is verified using the public key against
- the original data and against modified data.
- ('cipher/rsa.c:selftest_sign_1024')
- 4. A 1000 bit random value is encrypted and checked that it does
- not match the original random value. The encrypted result is
- then decrypted and checked that it matches the original random
- value. ('cipher/rsa.c:selftest_encr_1024')
-
-DSA
- A pre-defined 1024 bit DSA key is used and these tests are run in
- turn:
- 1. Conversion of S-expression to internal format.
- ('cipher/dsa.c:selftests_dsa')
- 2. Private key consistency check. ('cipher/dsa.c:selftests_dsa')
- 3. A pre-defined 20 byte value is signed with PKCS#1 padding for
- SHA-1. The result is verified using the public key against
- the original data and against modified data.
- ('cipher/dsa.c:selftest_sign_1024')
-
-A.1.6 Integrity Power-Up Tests
-------------------------------
-
-The integrity of the Libgcrypt is tested during power-up but only if
-checking has been enabled at build time. The check works by computing a
-HMAC SHA-256 checksum over the file used to load Libgcrypt into memory.
-That checksum is compared against a checksum stored in a file of the
-same name but with a single dot as a prefix and a suffix of '.hmac'.
-
-A.1.7 Critical Functions Power-Up Tests
----------------------------------------
-
-The 3DES weak key detection is tested during power-up by calling the
-detection function with keys taken from a table listening all weak keys.
-The table itself is protected using a SHA-1 hash.
-('cipher/des.c:selftest')
-
-A.2 Conditional Tests
-=====================
-
-The conditional tests are performed if a certain condition is met. This
-may occur at any time; the library does not necessary enter the
-"Self-Test" state to run these tests but will transit to the "Error"
-state if a test failed.
-
-A.2.1 Key-Pair Generation Tests
--------------------------------
-
-After an asymmetric key-pair has been generated, Libgcrypt runs a
-pair-wise consistency tests on the generated key. On failure the
-generated key is not used, an error code is returned and, if in FIPS
-mode, the library is put into the "Error" state.
-
-RSA
- The test uses a random number 64 bits less the size of the modulus
- as plaintext and runs an encryption and decryption operation in
- turn. The encrypted value is checked to not match the plaintext
- and the result of the decryption is checked to match the plaintext.
-
- A new random number of the same size is generated, signed and
- verified to test the correctness of the signing operation. As a
- second signing test, the signature is modified by incrementing its
- value and then verified with the expected result that the
- verification fails. ('cipher/rsa.c:test_keys')
-DSA
- The test uses a random number of the size of the Q parameter to
- create a signature and then checks that the signature verifies. As
- a second signing test, the data is modified by incrementing its
- value and then verified against the signature with the expected
- result that the verification fails. ('cipher/dsa.c:test_keys')
-
-A.2.2 Software Load Tests
--------------------------
-
-No code is loaded at runtime.
-
-A.2.3 Manual Key Entry Tests
-----------------------------
-
-A manual key entry feature is not implemented in Libgcrypt.
-
-A.2.4 Continuous RNG Tests
---------------------------
-
-The continuous random number test is only used in FIPS mode. The RNG
-generates blocks of 128 bit size; the first block generated per context
-is saved in the context and another block is generated to be returned to
-the caller. Each block is compared against the saved block and then
-stored in the context. If a duplicated block is detected an error is
-signaled and the library is put into the "Fatal-Error" state.
-('random/random-fips.c:x931_aes_driver')
-
-A.3 Application Requested Tests
-===============================
-
-The application may requests tests at any time by means of the
-'GCRYCTL_SELFTEST' control command. Note that using these tests is not
-FIPS conform: Although Libgcrypt rejects all application requests for
-services while running self-tests, it does not ensure that no other
-operations of Libgcrypt are still being executed. Thus, in FIPS mode an
-application requesting self-tests needs to power-cycle Libgcrypt
-instead.
-
- When self-tests are requested, Libgcrypt runs all the tests it does
-during power-up as well as a few extra checks as described below.
-
-A.3.1 Symmetric Cipher Algorithm Tests
---------------------------------------
-
-The following symmetric encryption algorithm tests are run in addition
-to the power-up tests:
-
-AES-128
- A known answer tests with test vectors taken from NIST SP800-38a
- and using the high level functions is run for block modes CFB and
- OFB.
-
-A.3.2 Hash Algorithm Tests
---------------------------
-
-The following hash algorithm tests are run in addition to the power-up
-tests:
-
-SHA-1
-SHA-224
-SHA-256
- 1. A known answer test using a 56 byte string is run.
- 2. A known answer test using a string of one million letters "a"
- is run.
- ('cipher/sha1.c:selftests_sha1',
- 'cipher/sha256.c:selftests_sha224',
- 'cipher/sha256.c:selftests_sha256')
-SHA-384
-SHA-512
- 1. A known answer test using a 112 byte string is run.
- 2. A known answer test using a string of one million letters "a"
- is run.
- ('cipher/sha512.c:selftests_sha384',
- 'cipher/sha512.c:selftests_sha512')
-
-A.3.3 MAC Algorithm Tests
--------------------------
-
-The following MAC algorithm tests are run in addition to the power-up
-tests:
-
-HMAC SHA-1
- 1. A known answer test using 9 byte of data and a 20 byte key is
- run.
- 2. A known answer test using 9 byte of data and a 100 byte key is
- run.
- 3. A known answer test using 9 byte of data and a 49 byte key is
- run.
- ('cipher/hmac-tests.c:selftests_sha1')
-HMAC SHA-224
-HMAC SHA-256
-HMAC SHA-384
-HMAC SHA-512
- 1. A known answer test using 9 byte of data and a 20 byte key is
- run.
- 2. A known answer test using 50 byte of data and a 20 byte key is
- run.
- 3. A known answer test using 50 byte of data and a 26 byte key is
- run.
- 4. A known answer test using 54 byte of data and a 131 byte key
- is run.
- 5. A known answer test using 152 byte of data and a 131 byte key
- is run.
- ('cipher/hmac-tests.c:selftests_sha224',
- 'cipher/hmac-tests.c:selftests_sha256',
- 'cipher/hmac-tests.c:selftests_sha384',
- 'cipher/hmac-tests.c:selftests_sha512')
-
-\1f
-File: gcrypt.info, Node: FIPS Mode, Next: Library Copying, Prev: Self-Tests, Up: Top
-
-Appendix B Description of the FIPS Mode
-***************************************
-
-This appendix gives detailed information pertaining to the FIPS mode.
-In particular, the changes to the standard mode and the finite state
-machine are described. The self-tests required in this mode are
-described in the appendix on self-tests.
-
-B.1 Restrictions in FIPS Mode
-=============================
-
-If Libgcrypt is used in FIPS mode these restrictions are effective:
-
- * The cryptographic algorithms are restricted to this list:
-
- GCRY_CIPHER_3DES
- 3 key EDE Triple-DES symmetric encryption.
- GCRY_CIPHER_AES128
- AES 128 bit symmetric encryption.
- GCRY_CIPHER_AES192
- AES 192 bit symmetric encryption.
- GCRY_CIPHER_AES256
- AES 256 bit symmetric encryption.
- GCRY_MD_SHA1
- SHA-1 message digest.
- GCRY_MD_SHA224
- SHA-224 message digest.
- GCRY_MD_SHA256
- SHA-256 message digest.
- GCRY_MD_SHA384
- SHA-384 message digest.
- GCRY_MD_SHA512
- SHA-512 message digest.
- GCRY_MD_SHA1,GCRY_MD_FLAG_HMAC
- HMAC using a SHA-1 message digest.
- GCRY_MD_SHA224,GCRY_MD_FLAG_HMAC
- HMAC using a SHA-224 message digest.
- GCRY_MD_SHA256,GCRY_MD_FLAG_HMAC
- HMAC using a SHA-256 message digest.
- GCRY_MD_SHA384,GCRY_MD_FLAG_HMAC
- HMAC using a SHA-384 message digest.
- GCRY_MD_SHA512,GCRY_MD_FLAG_HMAC
- HMAC using a SHA-512 message digest.
- GCRY_PK_RSA
- RSA encryption and signing.
- GCRY_PK_DSA
- DSA signing.
-
- Note that the CRC algorithms are not considered cryptographic
- algorithms and thus are in addition available.
-
- * RSA key generation refuses to create a key with a keysize of less
- than 1024 bits.
-
- * DSA key generation refuses to create a key with a keysize other
- than 1024 bits.
-
- * The 'transient-key' flag for RSA and DSA key generation is ignored.
-
- * Support for the VIA Padlock engine is disabled.
-
- * FIPS mode may only be used on systems with a /dev/random device.
- Switching into FIPS mode on other systems will fail at runtime.
-
- * Saving and loading a random seed file is ignored.
-
- * An X9.31 style random number generator is used in place of the
- large-pool-CSPRNG generator.
-
- * The command 'GCRYCTL_ENABLE_QUICK_RANDOM' is ignored.
-
- * Message digest debugging is disabled.
-
- * All debug output related to cryptographic data is suppressed.
-
- * On-the-fly self-tests are not performed, instead self-tests are run
- before entering operational state.
-
- * The function 'gcry_set_allocation_handler' may not be used. If it
- is used Libgcrypt disables FIPS mode unless Enforced FIPS mode is
- enabled, in which case Libgcrypt will enter the error state.
-
- * The digest algorithm MD5 may not be used. If it is used Libgcrypt
- disables FIPS mode unless Enforced FIPS mode is enabled, in which
- case Libgcrypt will enter the error state.
-
- * In Enforced FIPS mode the command 'GCRYCTL_DISABLE_SECMEM' is
- ignored. In standard FIPS mode it disables FIPS mode.
-
- * A handler set by 'gcry_set_outofcore_handler' is ignored.
- * A handler set by 'gcry_set_fatalerror_handler' is ignored.
-
- Note that when we speak about disabling FIPS mode, it merely means
-that the function 'gcry_fips_mode_active' returns false; it does not
-mean that any non FIPS algorithms are allowed.
-
-B.2 FIPS Finite State Machine
-=============================
-
-The FIPS mode of libgcrypt implements a finite state machine (FSM) using
-8 states (*note Table B.1: tbl:fips-states.) and checks at runtime that
-only valid transitions (*note Table B.2: tbl:fips-state-transitions.)
-may happen.
-
- \0\b[image src="fips-fsm.png" alt="FIPS FSM Diagram"\0\b]
-
-Figure B.1: FIPS mode state diagram
-
-States used by the FIPS FSM:
-
-Power-Off
- Libgcrypt is not runtime linked to another application. This
- usually means that the library is not loaded into main memory.
- This state is documentation only.
-
-Power-On
- Libgcrypt is loaded into memory and API calls may be made.
- Compiler introduced constructor functions may be run. Note that
- Libgcrypt does not implement any arbitrary constructor functions to
- be called by the operating system
-
-Init
- The Libgcrypt initialization functions are performed and the
- library has not yet run any self-test.
-
-Self-Test
- Libgcrypt is performing self-tests.
-
-Operational
- Libgcrypt is in the operational state and all interfaces may be
- used.
-
-Error
- Libgrypt is in the error state. When calling any FIPS relevant
- interfaces they either return an error ('GPG_ERR_NOT_OPERATIONAL')
- or put Libgcrypt into the Fatal-Error state and won't return.
-
-Fatal-Error
- Libgcrypt is in a non-recoverable error state and will
- automatically transit into the Shutdown state.
-
-Shutdown
- Libgcrypt is about to be terminated and removed from the memory.
- The application may at this point still running cleanup handlers.
-
-Table B.1: FIPS mode states
-
-The valid state transitions (*note Figure B.1: fig:fips-fsm.) are:
-'1'
- Power-Off to Power-On is implicitly done by the OS loading
- Libgcrypt as a shared library and having it linked to an
- application.
-
-'2'
- Power-On to Init is triggered by the application calling the
- Libgcrypt initialization function 'gcry_check_version'.
-
-'3'
- Init to Self-Test is either triggered by a dedicated API call or
- implicit by invoking a libgrypt service controlled by the FSM.
-
-'4'
- Self-Test to Operational is triggered after all self-tests passed
- successfully.
-
-'5'
- Operational to Shutdown is an artificial state without any direct
- action in Libgcrypt. When reaching the Shutdown state the library
- is deinitialized and can't return to any other state again.
-
-'6'
- Shutdown to Power-off is the process of removing Libgcrypt from the
- computer's memory. For obvious reasons the Power-Off state can't
- be represented within Libgcrypt and thus this transition is for
- documentation only.
-
-'7'
- Operational to Error is triggered if Libgcrypt detected an
- application error which can't be returned to the caller but still
- allows Libgcrypt to properly run. In the Error state all FIPS
- relevant interfaces return an error code.
-
-'8'
- Error to Shutdown is similar to the Operational to Shutdown
- transition (5).
-
-'9'
- Error to Fatal-Error is triggered if Libgrypt detects an fatal
- error while already being in Error state.
-
-'10'
- Fatal-Error to Shutdown is automatically entered by Libgcrypt after
- having reported the error.
-
-'11'
- Power-On to Shutdown is an artificial state to document that
- Libgcrypt has not ye been initialized but the process is about to
- terminate.
-
-'12'
- Power-On to Fatal-Error will be triggered if certain Libgcrypt
- functions are used without having reached the Init state.
-
-'13'
- Self-Test to Fatal-Error is triggered by severe errors in Libgcrypt
- while running self-tests.
-
-'14'
- Self-Test to Error is triggered by a failed self-test.
-
-'15'
- Operational to Fatal-Error is triggered if Libcrypt encountered a
- non-recoverable error.
-
-'16'
- Operational to Self-Test is triggered if the application requested
- to run the self-tests again.
-
-'17'
- Error to Self-Test is triggered if the application has requested to
- run self-tests to get to get back into operational state after an
- error.
-
-'18'
- Init to Error is triggered by errors in the initialization code.
-
-'19'
- Init to Fatal-Error is triggered by non-recoverable errors in the
- initialization code.
-
-'20'
- Error to Error is triggered by errors while already in the Error
- state.
-
-Table B.2: FIPS mode state transitions
-
-B.3 FIPS Miscellaneous Information
-==================================
-
-Libgcrypt does not do any key management on itself; the application
-needs to care about it. Keys which are passed to Libgcrypt should be
-allocated in secure memory as available with the functions
-'gcry_malloc_secure' and 'gcry_calloc_secure'. By calling 'gcry_free'
-on this memory, the memory and thus the keys are overwritten with zero
-bytes before releasing the memory.
-
- For use with the random number generator, Libgcrypt generates 3
-internal keys which are stored in the encryption contexts used by the
-RNG. These keys are stored in secure memory for the lifetime of the
-process. Application are required to use 'GCRYCTL_TERM_SECMEM' before
-process termination. This will zero out the entire secure memory and
-thus also the encryption contexts with these keys.
-
-\1f
-File: gcrypt.info, Node: Library Copying, Next: Copying, Prev: FIPS Mode, Up: Top
-
-GNU Lesser General Public License
-*********************************
-
- Version 2.1, February 1999
-
- Copyright (C) 1991, 1999 Free Software Foundation, Inc.
- 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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-\1f
-File: gcrypt.info, Node: Copying, Next: Figures and Tables, Prev: Library Copying, Up: Top
-
-GNU General Public License
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-source code. And you must show them these terms so they know their
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-distribute and/or modify the software.
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- TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-
- 1. This License applies to any program or other work which contains a
- notice placed by the copyright holder saying it may be distributed
- under the terms of this General Public License. The "Program",
- below, refers to any such program or work, and a "work based on the
- Program" means either the Program or any derivative work under
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- portion of it, either verbatim or with modifications and/or
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- included without limitation in the term "modification".) Each
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- of running the Program is not restricted, and the output from the
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- any part thereof, to be licensed as a whole at no charge to
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- program under these conditions, and telling the user how to
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- identifiable sections of that work are not derived from the
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- to those sections when you distribute them as separate works. But
- when you distribute the same sections as part of a whole which is a
- work based on the Program, the distribution of the whole must be on
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- extend to the entire whole, and thus to each and every part
- regardless of who wrote it.
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- under Section 2) in object code or executable form under the terms
- of Sections 1 and 2 above provided that you also do one of the
- following:
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- 9. If the distribution and/or use of the Program is restricted in
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- 10. The Free Software Foundation may publish revised and/or new
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- END OF TERMS AND CONDITIONS
-
-How to Apply These Terms to Your New Programs
-=============================================
-
-If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these
-terms.
-
- To do so, attach the following notices to the program. It is safest
-to attach them to the start of each source file to most effectively
-convey the exclusion of warranty; and each file should have at least the
-"copyright" line and a pointer to where the full notice is found.
-
- ONE LINE TO GIVE THE PROGRAM'S NAME AND AN IDEA OF WHAT IT DOES.
- Copyright (C) 19YY NAME OF AUTHOR
-
- This program is free software; you can redistribute it and/or
- modify it under the terms of the GNU General Public License
- as published by the Free Software Foundation; either version 2
- of the License, or (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
-
- Also add information on how to contact you by electronic and paper
-mail.
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- If the program is interactive, make it output a short notice like
-this when it starts in an interactive mode:
-
- Gnomovision version 69, Copyright (C) 19YY NAME OF AUTHOR
- Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
- type `show w'. This is free software, and you are welcome
- to redistribute it under certain conditions; type `show c'
- for details.
-
- The hypothetical commands 'show w' and 'show c' should show the
-appropriate parts of the General Public License. Of course, the
-commands you use may be called something other than 'show w' and 'show
-c'; they could even be mouse-clicks or menu items--whatever suits your
-program.
-
- You should also get your employer (if you work as a programmer) or
-your school, if any, to sign a "copyright disclaimer" for the program,
-if necessary. Here is a sample; alter the names:
-
- Yoyodyne, Inc., hereby disclaims all copyright
- interest in the program `Gnomovision'
- (which makes passes at compilers) written
- by James Hacker.
-
- SIGNATURE OF TY COON, 1 April 1989
- Ty Coon, President of Vice
-
- This General Public License does not permit incorporating your
-program into proprietary programs. If your program is a subroutine
-library, you may consider it more useful to permit linking proprietary
-applications with the library. If this is what you want to do, use the
-GNU Library General Public License instead of this License.
-
-\1f
-File: gcrypt.info, Node: Figures and Tables, Next: Concept Index, Prev: Copying, Up: Top
-
-List of Figures and Tables
-**************************
-
-* Menu:
-
-* Figure 17.1: fig:subsystems. Libgcrypt subsystems
-* Figure B.1: fig:fips-fsm. FIPS mode state diagram
-
-* Menu:
-
-* Table B.1: tbl:fips-states. FIPS mode states
-* Table B.2: tbl:fips-state-transitions. FIPS mode state transitions
-
-\1f
-File: gcrypt.info, Node: Concept Index, Next: Function and Data Index, Prev: Figures and Tables, Up: Top
-
-Concept Index
-*************
-
-\0\b[index\0\b]
-* Menu:
-
-* /etc/gcrypt/fips_enabled: Configuration. (line 69)
-* /etc/gcrypt/hwf.deny: Configuration. (line 48)
-* /etc/gcrypt/random.conf: Configuration. (line 52)
-* /proc/cpuinfo: Configuration. (line 74)
-* /proc/self/auxv: Configuration. (line 74)
-* 3DES: Available ciphers. (line 14)
-* Advanced Encryption Standard: Available ciphers. (line 35)
-* AES: Available ciphers. (line 35)
-* AES-Wrap mode: Available cipher modes.
- (line 35)
-* Arcfour: Available ciphers. (line 52)
-* BLAKE2b-512, BLAKE2b-384, BLAKE2b-256, BLAKE2b-160: Available hash algorithms.
- (line 6)
-* BLAKE2s-256, BLAKE2s-224, BLAKE2s-160, BLAKE2s-128: Available hash algorithms.
- (line 6)
-* Blowfish: Available ciphers. (line 22)
-* bug emulation: Working with hash algorithms.
- (line 38)
-* Camellia: Available ciphers. (line 77)
-* CAST5: Available ciphers. (line 19)
-* CBC, Cipher Block Chaining mode: Available cipher modes.
- (line 23)
-* CBC-MAC: Working with cipher handles.
- (line 56)
-* CCM, Counter with CBC-MAC mode: Available cipher modes.
- (line 48)
-* CFB, Cipher Feedback mode: Available cipher modes.
- (line 17)
-* ChaCha20: Available ciphers. (line 92)
-* cipher text stealing: Working with cipher handles.
- (line 50)
-* comp: Cryptographic Functions.
- (line 13)
-* CRC32: Available hash algorithms.
- (line 6)
-* CTR, Counter mode: Available cipher modes.
- (line 32)
-* DES: Available ciphers. (line 57)
-* DES-EDE: Available ciphers. (line 14)
-* Digital Encryption Standard: Available ciphers. (line 14)
-* disable-jent: Configuration. (line 58)
-* ECB, Electronic Codebook mode: Available cipher modes.
- (line 13)
-* EdDSA: Cryptographic Functions.
- (line 33)
-* Enforced FIPS mode: Enabling FIPS mode. (line 29)
-* error codes: Error Values. (line 6)
-* error codes, list of: Error Sources. (line 6)
-* error codes, list of <1>: Error Codes. (line 6)
-* error codes, printing of: Error Strings. (line 6)
-* error sources: Error Values. (line 6)
-* error sources, printing of: Error Strings. (line 6)
-* error strings: Error Strings. (line 6)
-* error values: Error Values. (line 6)
-* error values, printing of: Error Strings. (line 6)
-* FIPS 140: Enabling FIPS mode. (line 6)
-* FIPS 186: Cryptographic Functions.
- (line 72)
-* FIPS 186 <1>: Public-Key Subsystem Architecture.
- (line 50)
-* FIPS 186-2: Cryptographic Functions.
- (line 80)
-* FIPS mode: Enabling FIPS mode. (line 6)
-* fips_enabled: Configuration. (line 69)
-* GCM, Galois/Counter Mode: Available cipher modes.
- (line 53)
-* GCRYPT_BARRETT: Configuration. (line 12)
-* GCRYPT_RNDUNIX_DBG: Configuration. (line 17)
-* GCRYPT_RNDUNIX_DBGALL: Configuration. (line 17)
-* GCRYPT_RNDW32_DBG: Configuration. (line 32)
-* GCRYPT_RNDW32_NOPERF: Configuration. (line 25)
-* GOST 28147-89: Available ciphers. (line 88)
-* GPL, GNU General Public License: Copying. (line 6)
-* hardware features: Hardware features. (line 6)
-* HAVAL: Available hash algorithms.
- (line 6)
-* HMAC: Working with hash algorithms.
- (line 28)
-* HMAC-GOSTR-3411-94: Available MAC algorithms.
- (line 6)
-* HMAC-MD2, HMAC-MD4, HMAC-MD5: Available MAC algorithms.
- (line 6)
-* HMAC-RIPE-MD-160: Available MAC algorithms.
- (line 6)
-* HMAC-SHA-1: Available MAC algorithms.
- (line 6)
-* HMAC-SHA-224, HMAC-SHA-256, HMAC-SHA-384, HMAC-SHA-512: Available MAC algorithms.
- (line 6)
-* HMAC-SHA3-224, HMAC-SHA3-256, HMAC-SHA3-384, HMAC-SHA3-512: Available MAC algorithms.
- (line 6)
-* HMAC-Stribog-256, HMAC-Stribog-512: Available MAC algorithms.
- (line 6)
-* HMAC-TIGER1: Available MAC algorithms.
- (line 6)
-* HMAC-Whirlpool: Available MAC algorithms.
- (line 6)
-* HOME: Configuration. (line 37)
-* IDEA: Available ciphers. (line 11)
-* LGPL, GNU Lesser General Public License: Library Copying. (line 6)
-* MD2, MD4, MD5: Available hash algorithms.
- (line 6)
-* no-blinding: Cryptographic Functions.
- (line 41)
-* no-keytest: Cryptographic Functions.
- (line 59)
-* nocomp: Cryptographic Functions.
- (line 13)
-* OAEP: Cryptographic Functions.
- (line 27)
-* OCB, OCB3: Available cipher modes.
- (line 63)
-* OFB, Output Feedback mode: Available cipher modes.
- (line 29)
-* only-urandom: Configuration. (line 61)
-* param: Cryptographic Functions.
- (line 47)
-* PKCS1: Cryptographic Functions.
- (line 23)
-* Poly1305 based AEAD mode with ChaCha20: Available cipher modes.
- (line 58)
-* PSS: Cryptographic Functions.
- (line 30)
-* RC2: Available ciphers. (line 69)
-* RC4: Available ciphers. (line 52)
-* rfc-2268: Available ciphers. (line 69)
-* RFC6979: Cryptographic Functions.
- (line 38)
-* Rijndael: Available ciphers. (line 35)
-* RIPE-MD-160: Available hash algorithms.
- (line 6)
-* Salsa20: Available ciphers. (line 81)
-* Salsa20/12: Available ciphers. (line 84)
-* Seed (cipher): Available ciphers. (line 72)
-* Serpent: Available ciphers. (line 65)
-* SHA-1: Available hash algorithms.
- (line 6)
-* SHA-224, SHA-256, SHA-384, SHA-512: Available hash algorithms.
- (line 6)
-* SHA3-224, SHA3-256, SHA3-384, SHA3-512, SHAKE128, SHAKE256: Available hash algorithms.
- (line 6)
-* sync mode (OpenPGP): Working with cipher handles.
- (line 46)
-* TIGER, TIGER1, TIGER2: Available hash algorithms.
- (line 6)
-* transient-key: Cryptographic Functions.
- (line 52)
-* Triple-DES: Available ciphers. (line 14)
-* Twofish: Available ciphers. (line 46)
-* Whirlpool: Available hash algorithms.
- (line 6)
-* X9.31: Cryptographic Functions.
- (line 65)
-* X9.31 <1>: Public-Key Subsystem Architecture.
- (line 50)
-* XTS, XTS mode: Available cipher modes.
- (line 74)
-
-\1f
-File: gcrypt.info, Node: Function and Data Index, Prev: Concept Index, Up: Top
-
-Function and Data Index
-***********************
-
-\0\b[index\0\b]
-* Menu:
-
-* AM_PATH_LIBGCRYPT: Building sources using Automake.
- (line 11)
-* gcry_buffer_t: Buffer description. (line 9)
-* gcry_calloc: Memory allocation. (line 15)
-* gcry_calloc_secure: Memory allocation. (line 22)
-* gcry_check_version: Initializing the library.
- (line 15)
-* gcry_cipher_algo_info: General cipher functions.
- (line 10)
-* gcry_cipher_algo_name: General cipher functions.
- (line 59)
-* gcry_cipher_authenticate: Working with cipher handles.
- (line 119)
-* gcry_cipher_checktag: Working with cipher handles.
- (line 136)
-* gcry_cipher_close: Working with cipher handles.
- (line 62)
-* gcry_cipher_ctl: Working with cipher handles.
- (line 224)
-* gcry_cipher_decrypt: Working with cipher handles.
- (line 177)
-* gcry_cipher_encrypt: Working with cipher handles.
- (line 154)
-* gcry_cipher_final: Working with cipher handles.
- (line 203)
-* gcry_cipher_gettag: Working with cipher handles.
- (line 125)
-* gcry_cipher_get_algo_blklen: General cipher functions.
- (line 51)
-* gcry_cipher_get_algo_keylen: General cipher functions.
- (line 41)
-* gcry_cipher_info: Working with cipher handles.
- (line 234)
-* gcry_cipher_map_name: General cipher functions.
- (line 66)
-* gcry_cipher_mode_from_oid: General cipher functions.
- (line 72)
-* gcry_cipher_open: Working with cipher handles.
- (line 9)
-* gcry_cipher_reset: Working with cipher handles.
- (line 107)
-* gcry_cipher_setctr: Working with cipher handles.
- (line 98)
-* gcry_cipher_setiv: Working with cipher handles.
- (line 86)
-* gcry_cipher_setkey: Working with cipher handles.
- (line 71)
-* gcry_cipher_sync: Working with cipher handles.
- (line 214)
-* gcry_control: Controlling the library.
- (line 6)
-* gcry_create_nonce: Retrieving random numbers.
- (line 27)
-* gcry_ctx_release: Context management. (line 13)
-* gcry_ctx_t: Context management. (line 10)
-* gcry_error: Error Values. (line 63)
-* gcry_error_from_errno: Error Values. (line 86)
-* gcry_error_t: Error Values. (line 24)
-* gcry_err_code: Error Values. (line 42)
-* gcry_err_code_from_errno: Error Values. (line 95)
-* gcry_err_code_t: Error Values. (line 6)
-* gcry_err_code_to_errno: Error Values. (line 100)
-* gcry_err_make: Error Values. (line 55)
-* gcry_err_make_from_errno: Error Values. (line 79)
-* gcry_err_source: Error Values. (line 48)
-* gcry_err_source_t: Error Values. (line 13)
-* gcry_fips_mode_active: Controlling the library.
- (line 252)
-* gcry_free: Memory allocation. (line 33)
-* gcry_get_config: Config reporting. (line 10)
-* gcry_handler_alloc_t: Allocation handler. (line 10)
-* gcry_handler_error_t: Error handler. (line 25)
-* gcry_handler_free_t: Allocation handler. (line 19)
-* gcry_handler_log_t: Logging handler. (line 6)
-* gcry_handler_no_mem_t: Error handler. (line 10)
-* gcry_handler_progress_t: Progress handler. (line 9)
-* gcry_handler_realloc_t: Allocation handler. (line 16)
-* gcry_handler_secure_check_t: Allocation handler. (line 13)
-* gcry_kdf_derive: Key Derivation. (line 9)
-* gcry_mac_algo_name: Working with MAC algorithms.
- (line 114)
-* gcry_mac_close: Working with MAC algorithms.
- (line 48)
-* gcry_mac_get_algo: Working with MAC algorithms.
- (line 105)
-* gcry_mac_get_algo_keylen: Working with MAC algorithms.
- (line 143)
-* gcry_mac_get_algo_maclen: Working with MAC algorithms.
- (line 137)
-* gcry_mac_map_name: Working with MAC algorithms.
- (line 121)
-* gcry_mac_open: Working with MAC algorithms.
- (line 9)
-* gcry_mac_read: Working with MAC algorithms.
- (line 82)
-* gcry_mac_reset: Working with MAC algorithms.
- (line 59)
-* gcry_mac_setiv: Working with MAC algorithms.
- (line 40)
-* gcry_mac_setkey: Working with MAC algorithms.
- (line 29)
-* gcry_mac_test_algo: Working with MAC algorithms.
- (line 130)
-* gcry_mac_verify: Working with MAC algorithms.
- (line 93)
-* gcry_mac_write: Working with MAC algorithms.
- (line 70)
-* gcry_malloc: Memory allocation. (line 6)
-* gcry_malloc_secure: Memory allocation. (line 12)
-* gcry_md_algo_name: Working with hash algorithms.
- (line 227)
-* gcry_md_close: Working with hash algorithms.
- (line 78)
-* gcry_md_copy: Working with hash algorithms.
- (line 101)
-* gcry_md_debug: Working with hash algorithms.
- (line 298)
-* gcry_md_enable: Working with hash algorithms.
- (line 57)
-* gcry_md_extract: Working with hash algorithms.
- (line 167)
-* gcry_md_final: Working with hash algorithms.
- (line 137)
-* gcry_md_get_algo: Working with hash algorithms.
- (line 275)
-* gcry_md_get_algo_dlen: Working with hash algorithms.
- (line 265)
-* gcry_md_get_asnoid: Working with hash algorithms.
- (line 244)
-* gcry_md_hash_buffer: Working with hash algorithms.
- (line 208)
-* gcry_md_hash_buffers: Working with hash algorithms.
- (line 182)
-* gcry_md_is_enabled: Working with hash algorithms.
- (line 288)
-* gcry_md_is_secure: Working with hash algorithms.
- (line 282)
-* gcry_md_map_name: Working with hash algorithms.
- (line 234)
-* gcry_md_open: Working with hash algorithms.
- (line 9)
-* gcry_md_putc: Working with hash algorithms.
- (line 126)
-* gcry_md_read: Working with hash algorithms.
- (line 151)
-* gcry_md_reset: Working with hash algorithms.
- (line 89)
-* gcry_md_setkey: Working with hash algorithms.
- (line 66)
-* gcry_md_test_algo: Working with hash algorithms.
- (line 258)
-* gcry_md_write: Working with hash algorithms.
- (line 115)
-* gcry_mpi_abs: Basic functions. (line 63)
-* gcry_mpi_add: Calculations. (line 8)
-* gcry_mpi_addm: Calculations. (line 19)
-* gcry_mpi_add_ui: Calculations. (line 14)
-* gcry_mpi_aprint: MPI formats. (line 59)
-* gcry_mpi_clear_bit: Bit manipulations. (line 21)
-* gcry_mpi_clear_flag: Miscellaneous. (line 77)
-* gcry_mpi_clear_highbit: Bit manipulations. (line 29)
-* gcry_mpi_cmp: Comparisons. (line 8)
-* gcry_mpi_cmp_ui: Comparisons. (line 17)
-* gcry_mpi_copy: Basic functions. (line 24)
-* gcry_mpi_div: Calculations. (line 61)
-* gcry_mpi_dump: MPI formats. (line 74)
-* gcry_mpi_ec_add: EC functions. (line 166)
-* gcry_mpi_ec_curve_point: EC functions. (line 185)
-* gcry_mpi_ec_decode_point: EC functions. (line 136)
-* gcry_mpi_ec_dup: EC functions. (line 160)
-* gcry_mpi_ec_get_affine: EC functions. (line 147)
-* gcry_mpi_ec_get_mpi: EC functions. (line 91)
-* gcry_mpi_ec_get_point: EC functions. (line 109)
-* gcry_mpi_ec_mul: EC functions. (line 179)
-* gcry_mpi_ec_new: EC functions. (line 69)
-* gcry_mpi_ec_set_mpi: EC functions. (line 122)
-* gcry_mpi_ec_set_point: EC functions. (line 129)
-* gcry_mpi_ec_sub: EC functions. (line 172)
-* gcry_mpi_gcd: Calculations. (line 78)
-* gcry_mpi_get_flag: Miscellaneous. (line 85)
-* gcry_mpi_get_nbits: Bit manipulations. (line 9)
-* gcry_mpi_get_opaque: Miscellaneous. (line 31)
-* gcry_mpi_invm: Calculations. (line 84)
-* gcry_mpi_is_neg: Comparisons. (line 23)
-* gcry_mpi_lshift: Bit manipulations. (line 39)
-* gcry_mpi_mod: Calculations. (line 68)
-* gcry_mpi_mul: Calculations. (line 40)
-* gcry_mpi_mulm: Calculations. (line 51)
-* gcry_mpi_mul_2exp: Calculations. (line 56)
-* gcry_mpi_mul_ui: Calculations. (line 46)
-* gcry_mpi_neg: Basic functions. (line 59)
-* gcry_mpi_new: Basic functions. (line 9)
-* gcry_mpi_point_copy: EC functions. (line 23)
-* gcry_mpi_point_get: EC functions. (line 31)
-* gcry_mpi_point_new: EC functions. (line 10)
-* gcry_mpi_point_release: EC functions. (line 18)
-* gcry_mpi_point_set: EC functions. (line 47)
-* gcry_mpi_point_snatch_get: EC functions. (line 38)
-* gcry_mpi_point_snatch_set: EC functions. (line 57)
-* gcry_mpi_point_t: Data types. (line 9)
-* gcry_mpi_powm: Calculations. (line 73)
-* gcry_mpi_print: MPI formats. (line 49)
-* gcry_mpi_randomize: Miscellaneous. (line 94)
-* gcry_mpi_release: Basic functions. (line 29)
-* gcry_mpi_rshift: Bit manipulations. (line 33)
-* gcry_mpi_scan: MPI formats. (line 9)
-* gcry_mpi_set: Basic functions. (line 37)
-* gcry_mpi_set_bit: Bit manipulations. (line 17)
-* gcry_mpi_set_flag: Miscellaneous. (line 69)
-* gcry_mpi_set_highbit: Bit manipulations. (line 25)
-* gcry_mpi_set_opaque: Miscellaneous. (line 9)
-* gcry_mpi_set_opaque_copy: Miscellaneous. (line 25)
-* gcry_mpi_set_ui: Basic functions. (line 42)
-* gcry_mpi_snatch: Basic functions. (line 54)
-* gcry_mpi_snew: Basic functions. (line 17)
-* gcry_mpi_sub: Calculations. (line 24)
-* gcry_mpi_subm: Calculations. (line 35)
-* gcry_mpi_sub_ui: Calculations. (line 30)
-* gcry_mpi_swap: Basic functions. (line 50)
-* gcry_mpi_t: Data types. (line 6)
-* gcry_mpi_test_bit: Bit manipulations. (line 13)
-* gcry_pk_algo_info: General public-key related Functions.
- (line 49)
-* gcry_pk_algo_name: General public-key related Functions.
- (line 9)
-* gcry_pk_ctl: General public-key related Functions.
- (line 101)
-* gcry_pk_decrypt: Cryptographic Functions.
- (line 148)
-* gcry_pk_encrypt: Cryptographic Functions.
- (line 91)
-* gcry_pk_genkey: General public-key related Functions.
- (line 119)
-* gcry_pk_get_keygrip: General public-key related Functions.
- (line 31)
-* gcry_pk_get_nbits: General public-key related Functions.
- (line 26)
-* gcry_pk_map_name: General public-key related Functions.
- (line 16)
-* gcry_pk_sign: Cryptographic Functions.
- (line 187)
-* gcry_pk_testkey: General public-key related Functions.
- (line 43)
-* gcry_pk_test_algo: General public-key related Functions.
- (line 21)
-* gcry_pk_verify: Cryptographic Functions.
- (line 278)
-* gcry_prime_check: Checking. (line 6)
-* gcry_prime_generate: Generation. (line 6)
-* gcry_prime_group_generator: Generation. (line 18)
-* gcry_prime_release_factors: Generation. (line 26)
-* gcry_pubkey_get_sexp: General public-key related Functions.
- (line 311)
-* gcry_randomize: Retrieving random numbers.
- (line 6)
-* gcry_random_bytes: Retrieving random numbers.
- (line 12)
-* gcry_random_bytes_secure: Retrieving random numbers.
- (line 19)
-* gcry_random_level_t: Quality of random numbers.
- (line 8)
-* gcry_realloc: Memory allocation. (line 25)
-* gcry_set_allocation_handler: Allocation handler. (line 25)
-* gcry_set_fatalerror_handler: Error handler. (line 29)
-* gcry_set_log_handler: Logging handler. (line 10)
-* gcry_set_outofcore_handler: Error handler. (line 13)
-* gcry_set_progress_handler: Progress handler. (line 19)
-* gcry_sexp_build: Working with S-expressions.
- (line 46)
-* gcry_sexp_canon_len: Working with S-expressions.
- (line 134)
-* gcry_sexp_car: Working with S-expressions.
- (line 168)
-* gcry_sexp_cdr: Working with S-expressions.
- (line 175)
-* gcry_sexp_create: Working with S-expressions.
- (line 24)
-* gcry_sexp_dump: Working with S-expressions.
- (line 125)
-* gcry_sexp_extract_param: Working with S-expressions.
- (line 244)
-* gcry_sexp_find_token: Working with S-expressions.
- (line 146)
-* gcry_sexp_length: Working with S-expressions.
- (line 155)
-* gcry_sexp_new: Working with S-expressions.
- (line 11)
-* gcry_sexp_nth: Working with S-expressions.
- (line 160)
-* gcry_sexp_nth_buffer: Working with S-expressions.
- (line 202)
-* gcry_sexp_nth_data: Working with S-expressions.
- (line 183)
-* gcry_sexp_nth_mpi: Working with S-expressions.
- (line 232)
-* gcry_sexp_nth_string: Working with S-expressions.
- (line 224)
-* gcry_sexp_release: Working with S-expressions.
- (line 89)
-* gcry_sexp_sprint: Working with S-expressions.
- (line 100)
-* gcry_sexp_sscan: Working with S-expressions.
- (line 39)
-* gcry_sexp_t: Data types for S-expressions.
- (line 6)
-* gcry_strerror: Error Strings. (line 6)
-* gcry_strsource: Error Strings. (line 12)
-
-
+Indirect:
+gcrypt.info-1: 835
+gcrypt.info-2: 300845
\1f
Tag Table:
+(Indirect)
Node: Top\7f835
Node: Introduction\7f3361
Node: Getting Started\7f3733
Ref: Hardware features-Footnote-1\7f21502
Node: Generalities\7f21663
Node: Controlling the library\7f21922
-Node: Error Handling\7f40084
-Node: Error Values\7f42623
-Node: Error Sources\7f47563
-Node: Error Codes\7f49831
-Node: Error Strings\7f53307
-Node: Handler Functions\7f54491
-Node: Progress handler\7f55050
-Node: Allocation handler\7f57199
-Node: Error handler\7f58745
-Node: Logging handler\7f60311
-Node: Symmetric cryptography\7f60903
-Node: Available ciphers\7f61643
-Node: Available cipher modes\7f64324
-Node: Working with cipher handles\7f68177
-Node: General cipher functions\7f79681
-Node: Public Key cryptography\7f83207
-Node: Available algorithms\7f83973
-Node: Used S-expressions\7f84322
-Node: RSA key parameters\7f85439
-Node: DSA key parameters\7f86714
-Node: ECC key parameters\7f87368
-Ref: ecc_keyparam\7f87519
-Node: Cryptographic Functions\7f89390
-Node: General public-key related Functions\7f101209
-Node: Hashing\7f114729
-Node: Available hash algorithms\7f115462
-Node: Working with hash algorithms\7f121425
-Node: Message Authentication Codes\7f135557
-Node: Available MAC algorithms\7f136225
-Node: Working with MAC algorithms\7f141387
-Node: Key Derivation\7f147375
-Node: Random Numbers\7f149777
-Node: Quality of random numbers\7f150060
-Node: Retrieving random numbers\7f150743
-Node: S-expressions\7f152232
-Node: Data types for S-expressions\7f152877
-Node: Working with S-expressions\7f153203
-Node: MPI library\7f166868
-Node: Data types\7f167890
-Node: Basic functions\7f168199
-Node: MPI formats\7f170663
-Node: Calculations\7f174187
-Node: Comparisons\7f176456
-Node: Bit manipulations\7f177459
-Node: EC functions\7f178781
-Ref: gcry_mpi_ec_new\7f181730
-Node: Miscellaneous\7f187289
-Node: Prime numbers\7f191433
-Node: Generation\7f191703
-Node: Checking\7f192990
-Node: Utilities\7f193400
-Node: Memory allocation\7f193777
-Node: Context management\7f195133
-Ref: gcry_ctx_release\7f195571
-Node: Buffer description\7f195732
-Node: Config reporting\7f196519
-Node: Tools\7f197469
-Node: hmac256\7f197636
-Node: Configuration\7f198642
-Node: Architecture\7f201695
-Ref: fig:subsystems\7f203219
-Ref: Architecture-Footnote-1\7f204305
-Ref: Architecture-Footnote-2\7f204367
-Node: Public-Key Subsystem Architecture\7f204451
-Node: Symmetric Encryption Subsystem Architecture\7f206729
-Node: Hashing and MACing Subsystem Architecture\7f208175
-Node: Multi-Precision-Integer Subsystem Architecture\7f210098
-Node: Prime-Number-Generator Subsystem Architecture\7f211536
-Ref: Prime-Number-Generator Subsystem Architecture-Footnote-1\7f213467
-Node: Random-Number Subsystem Architecture\7f213759
-Node: CSPRNG Description\7f216708
-Ref: CSPRNG Description-Footnote-1\7f218264
-Node: FIPS PRNG Description\7f218387
-Node: Self-Tests\7f220521
-Node: FIPS Mode\7f231980
-Ref: fig:fips-fsm\7f235806
-Ref: tbl:fips-states\7f235909
-Ref: tbl:fips-state-transitions\7f237161
-Node: Library Copying\7f240782
-Node: Copying\7f268888
-Node: Figures and Tables\7f288064
-Node: Concept Index\7f288489
-Node: Function and Data Index\7f299824
+Node: Error Handling\7f40093
+Node: Error Values\7f42632
+Node: Error Sources\7f47572
+Node: Error Codes\7f49840
+Node: Error Strings\7f53316
+Node: Handler Functions\7f54500
+Node: Progress handler\7f55059
+Node: Allocation handler\7f57208
+Node: Error handler\7f58754
+Node: Logging handler\7f60320
+Node: Symmetric cryptography\7f60912
+Node: Available ciphers\7f61652
+Node: Available cipher modes\7f64333
+Node: Working with cipher handles\7f68186
+Node: General cipher functions\7f79690
+Node: Public Key cryptography\7f83216
+Node: Available algorithms\7f83982
+Node: Used S-expressions\7f84331
+Node: RSA key parameters\7f85448
+Node: DSA key parameters\7f86723
+Node: ECC key parameters\7f87377
+Ref: ecc_keyparam\7f87528
+Node: Cryptographic Functions\7f89399
+Node: General public-key related Functions\7f101246
+Node: Hashing\7f114915
+Node: Available hash algorithms\7f115648
+Node: Working with hash algorithms\7f121611
+Node: Message Authentication Codes\7f135743
+Node: Available MAC algorithms\7f136411
+Node: Working with MAC algorithms\7f141573
+Node: Key Derivation\7f147561
+Node: Random Numbers\7f149963
+Node: Quality of random numbers\7f150246
+Node: Retrieving random numbers\7f150929
+Node: S-expressions\7f152418
+Node: Data types for S-expressions\7f153063
+Node: Working with S-expressions\7f153389
+Node: MPI library\7f167054
+Node: Data types\7f168076
+Node: Basic functions\7f168385
+Node: MPI formats\7f170849
+Node: Calculations\7f174373
+Node: Comparisons\7f176642
+Node: Bit manipulations\7f177645
+Node: EC functions\7f178967
+Ref: gcry_mpi_ec_new\7f181916
+Node: Miscellaneous\7f187475
+Node: Prime numbers\7f191619
+Node: Generation\7f191889
+Node: Checking\7f193176
+Node: Utilities\7f193586
+Node: Memory allocation\7f193963
+Node: Context management\7f195319
+Ref: gcry_ctx_release\7f195757
+Node: Buffer description\7f195918
+Node: Config reporting\7f196705
+Node: Tools\7f197655
+Node: hmac256\7f197822
+Node: Configuration\7f198828
+Node: Architecture\7f201881
+Ref: fig:subsystems\7f203405
+Ref: Architecture-Footnote-1\7f204491
+Ref: Architecture-Footnote-2\7f204553
+Node: Public-Key Subsystem Architecture\7f204637
+Node: Symmetric Encryption Subsystem Architecture\7f206915
+Node: Hashing and MACing Subsystem Architecture\7f208361
+Node: Multi-Precision-Integer Subsystem Architecture\7f210284
+Node: Prime-Number-Generator Subsystem Architecture\7f211722
+Ref: Prime-Number-Generator Subsystem Architecture-Footnote-1\7f213653
+Node: Random-Number Subsystem Architecture\7f213945
+Node: CSPRNG Description\7f216894
+Ref: CSPRNG Description-Footnote-1\7f218450
+Node: FIPS PRNG Description\7f218573
+Node: Self-Tests\7f220707
+Node: FIPS Mode\7f232166
+Ref: fig:fips-fsm\7f235992
+Ref: tbl:fips-states\7f236095
+Ref: tbl:fips-state-transitions\7f237347
+Node: Library Copying\7f240968
+Node: Copying\7f269074
+Node: Figures and Tables\7f288250
+Node: Concept Index\7f288675
+Node: Function and Data Index\7f300845
\1f
End Tag Table
--- /dev/null
+This is gcrypt.info, produced by makeinfo version 6.3 from gcrypt.texi.
+
+This manual is for Libgcrypt (version 1.8.3, 13 June 2018), which is
+GNU's library of cryptographic building blocks.
+
+Copyright (C) 2000, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2011, 2012
+Free Software Foundation, Inc.
+Copyright (C) 2012, 2013, 2016, 2017 g10 Code GmbH
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version. The text of the
+ license can be found in the section entitled "GNU General Public
+ License".
+INFO-DIR-SECTION GNU Libraries
+START-INFO-DIR-ENTRY
+* libgcrypt: (gcrypt). Cryptographic function library.
+END-INFO-DIR-ENTRY
+
+\1f
+File: gcrypt.info, Node: Top, Next: Introduction, Up: (dir)
+
+The Libgcrypt Library
+*********************
+
+This manual is for Libgcrypt (version 1.8.3, 13 June 2018), which is
+GNU's library of cryptographic building blocks.
+
+Copyright (C) 2000, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2011, 2012
+Free Software Foundation, Inc.
+Copyright (C) 2012, 2013, 2016, 2017 g10 Code GmbH
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version. The text of the
+ license can be found in the section entitled "GNU General Public
+ License".
+
+* Menu:
+
+* Introduction:: What is Libgcrypt.
+* Preparation:: What you should do before using the library.
+* Generalities:: General library functions and data types.
+* Handler Functions:: Working with handler functions.
+* Symmetric cryptography:: How to use symmetric cryptography.
+* Public Key cryptography:: How to use public key cryptography.
+* Hashing:: How to use hash algorithms.
+* Message Authentication Codes:: How to use MAC algorithms.
+* Key Derivation:: How to derive keys from strings
+* Random Numbers:: How to work with random numbers.
+* S-expressions:: How to manage S-expressions.
+* MPI library:: How to work with multi-precision-integers.
+* Prime numbers:: How to use the Prime number related functions.
+* Utilities:: Utility functions.
+* Tools:: Utility tools.
+* Configuration:: Configuration files and environment variables.
+* Architecture:: How Libgcrypt works internally.
+
+Appendices
+
+* Self-Tests:: Description of the self-tests.
+* FIPS Mode:: Description of the FIPS mode.
+* Library Copying:: The GNU Lesser General Public License
+ says how you can copy and share Libgcrypt.
+* Copying:: The GNU General Public License says how you
+ can copy and share some parts of Libgcrypt.
+
+Indices
+
+* Figures and Tables:: Index of figures and tables.
+* Concept Index:: Index of concepts and programs.
+* Function and Data Index:: Index of functions, variables and data types.
+
+\1f
+File: gcrypt.info, Node: Introduction, Next: Preparation, Prev: Top, Up: Top
+
+1 Introduction
+**************
+
+Libgcrypt is a library providing cryptographic building blocks.
+
+* Menu:
+
+* Getting Started:: How to use this manual.
+* Features:: A glance at Libgcrypt's features.
+* Overview:: Overview about the library.
+
+\1f
+File: gcrypt.info, Node: Getting Started, Next: Features, Up: Introduction
+
+1.1 Getting Started
+===================
+
+This manual documents the Libgcrypt library application programming
+interface (API). All functions and data types provided by the library
+are explained.
+
+The reader is assumed to possess basic knowledge about applied
+cryptography.
+
+ This manual can be used in several ways. If read from the beginning
+to the end, it gives a good introduction into the library and how it can
+be used in an application. Forward references are included where
+necessary. Later on, the manual can be used as a reference manual to
+get just the information needed about any particular interface of the
+library. Experienced programmers might want to start looking at the
+examples at the end of the manual, and then only read up those parts of
+the interface which are unclear.
+
+\1f
+File: gcrypt.info, Node: Features, Next: Overview, Prev: Getting Started, Up: Introduction
+
+1.2 Features
+============
+
+Libgcrypt might have a couple of advantages over other libraries doing a
+similar job.
+
+It's Free Software
+ Anybody can use, modify, and redistribute it under the terms of the
+ GNU Lesser General Public License (*note Library Copying::). Note,
+ that some parts (which are in general not needed by applications)
+ are subject to the terms of the GNU General Public License (*note
+ Copying::); please see the README file of the distribution for of
+ list of these parts.
+
+It encapsulates the low level cryptography
+ Libgcrypt provides a high level interface to cryptographic building
+ blocks using an extensible and flexible API.
+
+\1f
+File: gcrypt.info, Node: Overview, Prev: Features, Up: Introduction
+
+1.3 Overview
+============
+
+The Libgcrypt library is fully thread-safe, where it makes sense to be
+thread-safe. Not thread-safe are some cryptographic functions that
+modify a certain context stored in handles. If the user really intents
+to use such functions from different threads on the same handle, he has
+to take care of the serialization of such functions himself. If not
+described otherwise, every function is thread-safe.
+
+ Libgcrypt depends on the library 'libgpg-error', which contains some
+common code used by other GnuPG components.
+
+\1f
+File: gcrypt.info, Node: Preparation, Next: Generalities, Prev: Introduction, Up: Top
+
+2 Preparation
+*************
+
+To use Libgcrypt, you have to perform some changes to your sources and
+the build system. The necessary changes are small and explained in the
+following sections. At the end of this chapter, it is described how the
+library is initialized, and how the requirements of the library are
+verified.
+
+* Menu:
+
+* Header:: What header file you need to include.
+* Building sources:: How to build sources using the library.
+* Building sources using Automake:: How to build sources with the help of Automake.
+* Initializing the library:: How to initialize the library.
+* Multi-Threading:: How Libgcrypt can be used in a MT environment.
+* Enabling FIPS mode:: How to enable the FIPS mode.
+* Hardware features:: How to disable hardware features.
+
+\1f
+File: gcrypt.info, Node: Header, Next: Building sources, Up: Preparation
+
+2.1 Header
+==========
+
+All interfaces (data types and functions) of the library are defined in
+the header file 'gcrypt.h'. You must include this in all source files
+using the library, either directly or through some other header file,
+like this:
+
+ #include <gcrypt.h>
+
+ The name space of Libgcrypt is 'gcry_*' for function and type names
+and 'GCRY*' for other symbols. In addition the same name prefixes with
+one prepended underscore are reserved for internal use and should never
+be used by an application. Note that Libgcrypt uses libgpg-error, which
+uses 'gpg_*' as name space for function and type names and 'GPG_*' for
+other symbols, including all the error codes.
+
+Certain parts of gcrypt.h may be excluded by defining these macros:
+
+'GCRYPT_NO_MPI_MACROS'
+ Do not define the shorthand macros 'mpi_*' for 'gcry_mpi_*'.
+
+'GCRYPT_NO_DEPRECATED'
+ Do not include definitions for deprecated features. This is useful
+ to make sure that no deprecated features are used.
+
+\1f
+File: gcrypt.info, Node: Building sources, Next: Building sources using Automake, Prev: Header, Up: Preparation
+
+2.2 Building sources
+====================
+
+If you want to compile a source file including the 'gcrypt.h' header
+file, you must make sure that the compiler can find it in the directory
+hierarchy. This is accomplished by adding the path to the directory in
+which the header file is located to the compilers include file search
+path (via the '-I' option).
+
+ However, the path to the include file is determined at the time the
+source is configured. To solve this problem, Libgcrypt ships with a
+small helper program 'libgcrypt-config' that knows the path to the
+include file and other configuration options. The options that need to
+be added to the compiler invocation at compile time are output by the
+'--cflags' option to 'libgcrypt-config'. The following example shows
+how it can be used at the command line:
+
+ gcc -c foo.c `libgcrypt-config --cflags`
+
+ Adding the output of 'libgcrypt-config --cflags' to the compiler’s
+command line will ensure that the compiler can find the Libgcrypt header
+file.
+
+ A similar problem occurs when linking the program with the library.
+Again, the compiler has to find the library files. For this to work,
+the path to the library files has to be added to the library search path
+(via the '-L' option). For this, the option '--libs' to
+'libgcrypt-config' can be used. For convenience, this option also
+outputs all other options that are required to link the program with the
+Libgcrypt libraries (in particular, the '-lgcrypt' option). The example
+shows how to link 'foo.o' with the Libgcrypt library to a program 'foo'.
+
+ gcc -o foo foo.o `libgcrypt-config --libs`
+
+ Of course you can also combine both examples to a single command by
+specifying both options to 'libgcrypt-config':
+
+ gcc -o foo foo.c `libgcrypt-config --cflags --libs`
+
+\1f
+File: gcrypt.info, Node: Building sources using Automake, Next: Initializing the library, Prev: Building sources, Up: Preparation
+
+2.3 Building sources using Automake
+===================================
+
+It is much easier if you use GNU Automake instead of writing your own
+Makefiles. If you do that, you do not have to worry about finding and
+invoking the 'libgcrypt-config' script at all. Libgcrypt provides an
+extension to Automake that does all the work for you.
+
+ -- Macro: AM_PATH_LIBGCRYPT ([MINIMUM-VERSION], [ACTION-IF-FOUND],
+ [ACTION-IF-NOT-FOUND])
+ Check whether Libgcrypt (at least version MINIMUM-VERSION, if
+ given) exists on the host system. If it is found, execute
+ ACTION-IF-FOUND, otherwise do ACTION-IF-NOT-FOUND, if given.
+
+ Additionally, the function defines 'LIBGCRYPT_CFLAGS' to the flags
+ needed for compilation of the program to find the 'gcrypt.h' header
+ file, and 'LIBGCRYPT_LIBS' to the linker flags needed to link the
+ program to the Libgcrypt library. If the used helper script does
+ not match the target type you are building for a warning is printed
+ and the string 'libgcrypt' is appended to the variable
+ 'gpg_config_script_warn'.
+
+ This macro searches for 'libgcrypt-config' along the PATH. If you
+ are cross-compiling, it is useful to set the environment variable
+ 'SYSROOT' to the top directory of your target. The macro will then
+ first look for the helper program in the 'bin' directory below that
+ top directory. An absolute directory name must be used for
+ 'SYSROOT'. Finally, if the configure command line option
+ '--with-libgcrypt-prefix' is used, only its value is used for the
+ top directory below which the helper script is expected.
+
+ You can use the defined Autoconf variables like this in your
+'Makefile.am':
+
+ AM_CPPFLAGS = $(LIBGCRYPT_CFLAGS)
+ LDADD = $(LIBGCRYPT_LIBS)
+
+\1f
+File: gcrypt.info, Node: Initializing the library, Next: Multi-Threading, Prev: Building sources using Automake, Up: Preparation
+
+2.4 Initializing the library
+============================
+
+Before the library can be used, it must initialize itself. This is
+achieved by invoking the function 'gcry_check_version' described below.
+
+ Also, it is often desirable to check that the version of Libgcrypt
+used is indeed one which fits all requirements. Even with binary
+compatibility, new features may have been introduced, but due to problem
+with the dynamic linker an old version may actually be used. So you may
+want to check that the version is okay right after program startup.
+
+ -- Function: const char * gcry_check_version (const char *REQ_VERSION)
+
+ The function 'gcry_check_version' initializes some subsystems used
+ by Libgcrypt and must be invoked before any other function in the
+ library. *Note Multi-Threading::.
+
+ Furthermore, this function returns the version number of the
+ library. It can also verify that the version number is higher than
+ a certain required version number REQ_VERSION, if this value is not
+ a null pointer.
+
+ Libgcrypt uses a concept known as secure memory, which is a region of
+memory set aside for storing sensitive data. Because such memory is a
+scarce resource, it needs to be setup in advanced to a fixed size.
+Further, most operating systems have special requirements on how that
+secure memory can be used. For example, it might be required to install
+an application as "setuid(root)" to allow allocating such memory.
+Libgcrypt requires a sequence of initialization steps to make sure that
+this works correctly. The following examples show the necessary steps.
+
+ If you don't have a need for secure memory, for example if your
+application does not use secret keys or other confidential data or it
+runs in a controlled environment where key material floating around in
+memory is not a problem, you should initialize Libgcrypt this way:
+
+ /* Version check should be the very first call because it
+ makes sure that important subsystems are initialized. */
+ if (!gcry_check_version (GCRYPT_VERSION))
+ {
+ fputs ("libgcrypt version mismatch\n", stderr);
+ exit (2);
+ }
+
+ /* Disable secure memory. */
+ gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
+
+ /* ... If required, other initialization goes here. */
+
+ /* Tell Libgcrypt that initialization has completed. */
+ gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
+
+ If you have to protect your keys or other information in memory
+against being swapped out to disk and to enable an automatic overwrite
+of used and freed memory, you need to initialize Libgcrypt this way:
+
+ /* Version check should be the very first call because it
+ makes sure that important subsystems are initialized. */
+ if (!gcry_check_version (GCRYPT_VERSION))
+ {
+ fputs ("libgcrypt version mismatch\n", stderr);
+ exit (2);
+ }
+
+ /* We don't want to see any warnings, e.g. because we have not yet
+ parsed program options which might be used to suppress such
+ warnings. */
+ gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN);
+
+ /* ... If required, other initialization goes here. Note that the
+ process might still be running with increased privileges and that
+ the secure memory has not been initialized. */
+
+ /* Allocate a pool of 16k secure memory. This makes the secure memory
+ available and also drops privileges where needed. Note that by
+ using functions like gcry_xmalloc_secure and gcry_mpi_snew Libgcrypt
+ may expand the secure memory pool with memory which lacks the
+ property of not being swapped out to disk. */
+ gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
+
+ /* It is now okay to let Libgcrypt complain when there was/is
+ a problem with the secure memory. */
+ gcry_control (GCRYCTL_RESUME_SECMEM_WARN);
+
+ /* ... If required, other initialization goes here. */
+
+ /* Tell Libgcrypt that initialization has completed. */
+ gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
+
+ It is important that these initialization steps are not done by a
+library but by the actual application. A library using Libgcrypt might
+want to check for finished initialization using:
+
+ if (!gcry_control (GCRYCTL_INITIALIZATION_FINISHED_P))
+ {
+ fputs ("libgcrypt has not been initialized\n", stderr);
+ abort ();
+ }
+
+ Instead of terminating the process, the library may instead print a
+warning and try to initialize Libgcrypt itself. See also the section on
+multi-threading below for more pitfalls.
+
+\1f
+File: gcrypt.info, Node: Multi-Threading, Next: Enabling FIPS mode, Prev: Initializing the library, Up: Preparation
+
+2.5 Multi-Threading
+===================
+
+As mentioned earlier, the Libgcrypt library is thread-safe if you adhere
+to the following requirements:
+
+ * If you use pthread and your applications forks and does not
+ directly call exec (even calling stdio functions), all kind of
+ problems may occur. Future versions of Libgcrypt will try to
+ cleanup using pthread_atfork but even that may lead to problems.
+ This is a common problem with almost all applications using pthread
+ and fork.
+
+ * The function 'gcry_check_version' must be called before any other
+ function in the library. To achieve this in multi-threaded
+ programs, you must synchronize the memory with respect to other
+ threads that also want to use Libgcrypt. For this, it is
+ sufficient to call 'gcry_check_version' before creating the other
+ threads using Libgcrypt(1).
+
+ * Just like the function 'gpg_strerror', the function 'gcry_strerror'
+ is not thread safe. You have to use 'gpg_strerror_r' instead.
+
+ ---------- Footnotes ----------
+
+ (1) At least this is true for POSIX threads, as 'pthread_create' is a
+function that synchronizes memory with respects to other threads. There
+are many functions which have this property, a complete list can be
+found in POSIX, IEEE Std 1003.1-2003, Base Definitions, Issue 6, in the
+definition of the term "Memory Synchronization". For other thread
+packages, more relaxed or more strict rules may apply.
+
+\1f
+File: gcrypt.info, Node: Enabling FIPS mode, Next: Hardware features, Prev: Multi-Threading, Up: Preparation
+
+2.6 How to enable the FIPS mode
+===============================
+
+Libgcrypt may be used in a FIPS 140-2 mode. Note, that this does not
+necessary mean that Libcgrypt is an appoved FIPS 140-2 module. Check
+the NIST database at <http://csrc.nist.gov/groups/STM/cmvp/> to see what
+versions of Libgcrypt are approved.
+
+ Because FIPS 140 has certain restrictions on the use of cryptography
+which are not always wanted, Libgcrypt needs to be put into FIPS mode
+explicitly. Three alternative mechanisms are provided to switch
+Libgcrypt into this mode:
+
+ * If the file '/proc/sys/crypto/fips_enabled' exists and contains a
+ numeric value other than '0', Libgcrypt is put into FIPS mode at
+ initialization time. Obviously this works only on systems with a
+ 'proc' file system (i.e. GNU/Linux).
+
+ * If the file '/etc/gcrypt/fips_enabled' exists, Libgcrypt is put
+ into FIPS mode at initialization time. Note that this filename is
+ hardwired and does not depend on any configuration options.
+
+ * If the application requests FIPS mode using the control command
+ 'GCRYCTL_FORCE_FIPS_MODE'. This must be done prior to any
+ initialization (i.e. before 'gcry_check_version').
+
+ In addition to the standard FIPS mode, Libgcrypt may also be put into
+an Enforced FIPS mode by writing a non-zero value into the file
+'/etc/gcrypt/fips_enabled' or by using the control command
+'GCRYCTL_SET_ENFORCED_FIPS_FLAG' before any other calls to libgcrypt.
+The Enforced FIPS mode helps to detect applications which don't fulfill
+all requirements for using Libgcrypt in FIPS mode (*note FIPS Mode::).
+
+ Once Libgcrypt has been put into FIPS mode, it is not possible to
+switch back to standard mode without terminating the process first. If
+the logging verbosity level of Libgcrypt has been set to at least 2, the
+state transitions and the self-tests are logged.
+
+\1f
+File: gcrypt.info, Node: Hardware features, Prev: Enabling FIPS mode, Up: Preparation
+
+2.7 How to disable hardware features
+====================================
+
+Libgcrypt makes use of certain hardware features. If the use of a
+feature is not desired it may be either be disabled by a program or
+globally using a configuration file. The currently supported features
+are
+
+'padlock-rng'
+'padlock-aes'
+'padlock-sha'
+'padlock-mmul'
+'intel-cpu'
+'intel-fast-shld'
+'intel-bmi2'
+'intel-ssse3'
+'intel-pclmul'
+'intel-aesni'
+'intel-rdrand'
+'intel-avx'
+'intel-avx2'
+'intel-rdtsc'
+'arm-neon'
+
+ To disable a feature for all processes using Libgcrypt 1.6 or newer,
+create the file '/etc/gcrypt/hwf.deny' and put each feature not to be
+used on a single line. Empty lines, white space, and lines prefixed
+with a hash mark are ignored. The file should be world readable.
+
+ To disable a feature specifically for a program that program must
+tell it Libgcrypt before before calling 'gcry_check_version'.
+Example:(1)
+
+ gcry_control (GCRYCTL_DISABLE_HWF, "intel-rdrand", NULL);
+
+To print the list of active features you may use this command:
+
+ mpicalc --print-config | grep ^hwflist: | tr : '\n' | tail -n +2
+
+ ---------- Footnotes ----------
+
+ (1) NB. Libgcrypt uses the RDRAND feature only as one source of
+entropy. A CPU with a broken RDRAND will thus not compromise of the
+random number generator
+
+\1f
+File: gcrypt.info, Node: Generalities, Next: Handler Functions, Prev: Preparation, Up: Top
+
+3 Generalities
+**************
+
+* Menu:
+
+* Controlling the library:: Controlling Libgcrypt's behavior.
+* Error Handling:: Error codes and such.
+
+\1f
+File: gcrypt.info, Node: Controlling the library, Next: Error Handling, Up: Generalities
+
+3.1 Controlling the library
+===========================
+
+ -- Function: gcry_error_t gcry_control (enum gcry_ctl_cmds CMD, ...)
+
+ This function can be used to influence the general behavior of
+ Libgcrypt in several ways. Depending on CMD, more arguments can or
+ have to be provided.
+
+ 'GCRYCTL_ENABLE_M_GUARD; Arguments: none'
+ This command enables the built-in memory guard. It must not
+ be used to activate the memory guard after the memory
+ management has already been used; therefore it can ONLY be
+ used before 'gcry_check_version'. Note that the memory guard
+ is NOT used when the user of the library has set his own
+ memory management callbacks.
+
+ 'GCRYCTL_ENABLE_QUICK_RANDOM; Arguments: none'
+ This command inhibits the use the very secure random quality
+ level ('GCRY_VERY_STRONG_RANDOM') and degrades all request
+ down to 'GCRY_STRONG_RANDOM'. In general this is not
+ recommended. However, for some applications the extra quality
+ random Libgcrypt tries to create is not justified and this
+ option may help to get better performance. Please check with
+ a crypto expert whether this option can be used for your
+ application.
+
+ This option can only be used at initialization time.
+
+ 'GCRYCTL_DUMP_RANDOM_STATS; Arguments: none'
+ This command dumps random number generator related statistics
+ to the library's logging stream.
+
+ 'GCRYCTL_DUMP_MEMORY_STATS; Arguments: none'
+ This command dumps memory management related statistics to the
+ library's logging stream.
+
+ 'GCRYCTL_DUMP_SECMEM_STATS; Arguments: none'
+ This command dumps secure memory management related statistics
+ to the library's logging stream.
+
+ 'GCRYCTL_DROP_PRIVS; Arguments: none'
+ This command disables the use of secure memory and drops the
+ privileges of the current process. This command has not much
+ use; the suggested way to disable secure memory is to use
+ 'GCRYCTL_DISABLE_SECMEM' right after initialization.
+
+ 'GCRYCTL_DISABLE_SECMEM; Arguments: none'
+ This command disables the use of secure memory. If this
+ command is used in FIPS mode, FIPS mode will be disabled and
+ the function 'gcry_fips_mode_active' returns false. However,
+ in Enforced FIPS mode this command has no effect at all.
+
+ Many applications do not require secure memory, so they should
+ disable it right away. This command should be executed right
+ after 'gcry_check_version'.
+
+ 'GCRYCTL_DISABLE_LOCKED_SECMEM; Arguments: none'
+ This command disables the use of the mlock call for secure
+ memory. Disabling the use of mlock may for example be done if
+ an encrypted swap space is in use. This command should be
+ executed right after 'gcry_check_version'. Note that by using
+ functions like gcry_xmalloc_secure and gcry_mpi_snew Libgcrypt
+ may expand the secure memory pool with memory which lacks the
+ property of not being swapped out to disk (but will still be
+ zeroed out on free).
+
+ 'GCRYCTL_DISABLE_PRIV_DROP; Arguments: none'
+ This command sets a global flag to tell the secure memory
+ subsystem that it shall not drop privileges after secure
+ memory has been allocated. This command is commonly used
+ right after 'gcry_check_version' but may also be used right
+ away at program startup. It won't have an effect after the
+ secure memory pool has been initialized. WARNING: A process
+ running setuid(root) is a severe security risk. Processes
+ making use of Libgcrypt or other complex code should drop
+ these extra privileges as soon as possible. If this command
+ has been used the caller is responsible for dropping the
+ privileges.
+
+ 'GCRYCTL_INIT_SECMEM; Arguments: unsigned int nbytes'
+ This command is used to allocate a pool of secure memory and
+ thus enabling the use of secure memory. It also drops all
+ extra privileges the process has (i.e. if it is run as setuid
+ (root)). If the argument NBYTES is 0, secure memory will be
+ disabled. The minimum amount of secure memory allocated is
+ currently 16384 bytes; you may thus use a value of 1 to
+ request that default size.
+
+ 'GCRYCTL_TERM_SECMEM; Arguments: none'
+ This command zeroises the secure memory and destroys the
+ handler. The secure memory pool may not be used anymore after
+ running this command. If the secure memory pool as already
+ been destroyed, this command has no effect. Applications
+ might want to run this command from their exit handler to make
+ sure that the secure memory gets properly destroyed. This
+ command is not necessarily thread-safe but that should not be
+ needed in cleanup code. It may be called from a signal
+ handler.
+
+ 'GCRYCTL_DISABLE_SECMEM_WARN; Arguments: none'
+ Disable warning messages about problems with the secure memory
+ subsystem. This command should be run right after
+ 'gcry_check_version'.
+
+ 'GCRYCTL_SUSPEND_SECMEM_WARN; Arguments: none'
+ Postpone warning messages from the secure memory subsystem.
+ *Note the initialization example: sample-use-suspend-secmem,
+ on how to use it.
+
+ 'GCRYCTL_RESUME_SECMEM_WARN; Arguments: none'
+ Resume warning messages from the secure memory subsystem.
+ *Note the initialization example: sample-use-resume-secmem, on
+ how to use it.
+
+ 'GCRYCTL_USE_SECURE_RNDPOOL; Arguments: none'
+ This command tells the PRNG to store random numbers in secure
+ memory. This command should be run right after
+ 'gcry_check_version' and not later than the command
+ GCRYCTL_INIT_SECMEM. Note that in FIPS mode the secure memory
+ is always used.
+
+ 'GCRYCTL_SET_RANDOM_SEED_FILE; Arguments: const char *filename'
+ This command specifies the file, which is to be used as seed
+ file for the PRNG. If the seed file is registered prior to
+ initialization of the PRNG, the seed file's content (if it
+ exists and seems to be valid) is fed into the PRNG pool.
+ After the seed file has been registered, the PRNG can be
+ signalled to write out the PRNG pool's content into the seed
+ file with the following command.
+
+ 'GCRYCTL_UPDATE_RANDOM_SEED_FILE; Arguments: none'
+ Write out the PRNG pool's content into the registered seed
+ file.
+
+ Multiple instances of the applications sharing the same random
+ seed file can be started in parallel, in which case they will
+ read out the same pool and then race for updating it (the last
+ update overwrites earlier updates). They will differentiate
+ only by the weak entropy that is added in read_seed_file based
+ on the PID and clock, and up to 16 bytes of weak random
+ non-blockingly. The consequence is that the output of these
+ different instances is correlated to some extent. In a
+ perfect attack scenario, the attacker can control (or at least
+ guess) the PID and clock of the application, and drain the
+ system's entropy pool to reduce the "up to 16 bytes" above to
+ 0. Then the dependencies of the initial states of the pools
+ are completely known. Note that this is not an issue if
+ random of 'GCRY_VERY_STRONG_RANDOM' quality is requested as in
+ this case enough extra entropy gets mixed. It is also not an
+ issue when using Linux (rndlinux driver), because this one
+ guarantees to read full 16 bytes from /dev/urandom and thus
+ there is no way for an attacker without kernel access to
+ control these 16 bytes.
+
+ 'GCRYCTL_CLOSE_RANDOM_DEVICE; Arguments: none'
+ Try to close the random device. If on Unix system you call
+ fork(), the child process does no call exec(), and you do not
+ intend to use Libgcrypt in the child, it might be useful to
+ use this control code to close the inherited file descriptors
+ of the random device. If Libgcrypt is later used again by the
+ child, the device will be re-opened. On non-Unix systems this
+ control code is ignored.
+
+ 'GCRYCTL_SET_VERBOSITY; Arguments: int level'
+ This command sets the verbosity of the logging. A level of 0
+ disables all extra logging whereas positive numbers enable
+ more verbose logging. The level may be changed at any time
+ but be aware that no memory synchronization is done so the
+ effect of this command might not immediately show up in other
+ threads. This command may even be used prior to
+ 'gcry_check_version'.
+
+ 'GCRYCTL_SET_DEBUG_FLAGS; Arguments: unsigned int flags'
+ Set the debug flag bits as given by the argument. Be aware
+ that that no memory synchronization is done so the effect of
+ this command might not immediately show up in other threads.
+ The debug flags are not considered part of the API and thus
+ may change without notice. As of now bit 0 enables debugging
+ of cipher functions and bit 1 debugging of
+ multi-precision-integers. This command may even be used prior
+ to 'gcry_check_version'.
+
+ 'GCRYCTL_CLEAR_DEBUG_FLAGS; Arguments: unsigned int flags'
+ Set the debug flag bits as given by the argument. Be aware
+ that that no memory synchronization is done so the effect of
+ this command might not immediately show up in other threads.
+ This command may even be used prior to 'gcry_check_version'.
+
+ 'GCRYCTL_DISABLE_INTERNAL_LOCKING; Arguments: none'
+ This command does nothing. It exists only for backward
+ compatibility.
+
+ 'GCRYCTL_ANY_INITIALIZATION_P; Arguments: none'
+ This command returns true if the library has been basically
+ initialized. Such a basic initialization happens implicitly
+ with many commands to get certain internal subsystems running.
+ The common and suggested way to do this basic initialization
+ is by calling gcry_check_version.
+
+ 'GCRYCTL_INITIALIZATION_FINISHED; Arguments: none'
+ This command tells the library that the application has
+ finished the initialization.
+
+ 'GCRYCTL_INITIALIZATION_FINISHED_P; Arguments: none'
+ This command returns true if the command
+ GCRYCTL_INITIALIZATION_FINISHED has already been run.
+
+ 'GCRYCTL_SET_THREAD_CBS; Arguments: struct ath_ops *ath_ops'
+ This command is obsolete since version 1.6.
+
+ 'GCRYCTL_FAST_POLL; Arguments: none'
+ Run a fast random poll.
+
+ 'GCRYCTL_SET_RNDEGD_SOCKET; Arguments: const char *filename'
+ This command may be used to override the default name of the
+ EGD socket to connect to. It may be used only during
+ initialization as it is not thread safe. Changing the socket
+ name again is not supported. The function may return an error
+ if the given filename is too long for a local socket name.
+
+ EGD is an alternative random gatherer, used only on systems
+ lacking a proper random device.
+
+ 'GCRYCTL_PRINT_CONFIG; Arguments: FILE *stream'
+ This command dumps information pertaining to the configuration
+ of the library to the given stream. If NULL is given for
+ STREAM, the log system is used. This command may be used
+ before the initialization has been finished but not before a
+ 'gcry_check_version'. Note that the macro 'estream_t' can be
+ used instead of 'gpgrt_stream_t'.
+
+ 'GCRYCTL_OPERATIONAL_P; Arguments: none'
+ This command returns true if the library is in an operational
+ state. This information makes only sense in FIPS mode. In
+ contrast to other functions, this is a pure test function and
+ won't put the library into FIPS mode or change the internal
+ state. This command may be used before the initialization has
+ been finished but not before a 'gcry_check_version'.
+
+ 'GCRYCTL_FIPS_MODE_P; Arguments: none'
+ This command returns true if the library is in FIPS mode.
+ Note, that this is no indication about the current state of
+ the library. This command may be used before the
+ initialization has been finished but not before a
+ 'gcry_check_version'. An application may use this command or
+ the convenience macro below to check whether FIPS mode is
+ actually active.
+
+ -- Function: int gcry_fips_mode_active (void)
+
+ Returns true if the FIPS mode is active. Note that this
+ is implemented as a macro.
+
+ 'GCRYCTL_FORCE_FIPS_MODE; Arguments: none'
+ Running this command puts the library into FIPS mode. If the
+ library is already in FIPS mode, a self-test is triggered and
+ thus the library will be put into operational state. This
+ command may be used before a call to 'gcry_check_version' and
+ that is actually the recommended way to let an application
+ switch the library into FIPS mode. Note that Libgcrypt will
+ reject an attempt to switch to fips mode during or after the
+ initialization.
+
+ 'GCRYCTL_SET_ENFORCED_FIPS_FLAG; Arguments: none'
+ Running this command sets the internal flag that puts the
+ library into the enforced FIPS mode during the FIPS mode
+ initialization. This command does not affect the library if
+ the library is not put into the FIPS mode and it must be used
+ before any other libgcrypt library calls that initialize the
+ library such as 'gcry_check_version'. Note that Libgcrypt
+ will reject an attempt to switch to the enforced fips mode
+ during or after the initialization.
+
+ 'GCRYCTL_SET_PREFERRED_RNG_TYPE; Arguments: int'
+ These are advisory commands to select a certain random number
+ generator. They are only advisory because libraries may not
+ know what an application actually wants or vice versa. Thus
+ Libgcrypt employs a priority check to select the actually used
+ RNG. If an applications selects a lower priority RNG but a
+ library requests a higher priority RNG Libgcrypt will switch
+ to the higher priority RNG. Applications and libraries should
+ use these control codes before 'gcry_check_version'. The
+ available generators are:
+ 'GCRY_RNG_TYPE_STANDARD'
+ A conservative standard generator based on the
+ "Continuously Seeded Pseudo Random Number Generator"
+ designed by Peter Gutmann.
+ 'GCRY_RNG_TYPE_FIPS'
+ A deterministic random number generator conforming to he
+ document "NIST-Recommended Random Number Generator Based
+ on ANSI X9.31 Appendix A.2.4 Using the 3-Key Triple DES
+ and AES Algorithms" (2005-01-31). This implementation
+ uses the AES variant.
+ 'GCRY_RNG_TYPE_SYSTEM'
+ A wrapper around the system's native RNG. On Unix system
+ these are usually the /dev/random and /dev/urandom
+ devices.
+ The default is 'GCRY_RNG_TYPE_STANDARD' unless FIPS mode as
+ been enabled; in which case 'GCRY_RNG_TYPE_FIPS' is used and
+ locked against further changes.
+
+ 'GCRYCTL_GET_CURRENT_RNG_TYPE; Arguments: int *'
+ This command stores the type of the currently used RNG as an
+ integer value at the provided address.
+
+ 'GCRYCTL_SELFTEST; Arguments: none'
+ This may be used at anytime to have the library run all
+ implemented self-tests. It works in standard and in FIPS
+ mode. Returns 0 on success or an error code on failure.
+
+ 'GCRYCTL_DISABLE_HWF; Arguments: const char *name'
+
+ Libgcrypt detects certain features of the CPU at startup time.
+ For performance tests it is sometimes required not to use such
+ a feature. This option may be used to disable a certain
+ feature; i.e. Libgcrypt behaves as if this feature has not
+ been detected. This call can be used several times to disable
+ a set of features, or features may be given as a colon or
+ comma delimited string. The special feature "all" can be used
+ to disable all available features.
+
+ Note that the detection code might be run if the feature has
+ been disabled. This command must be used at initialization
+ time; i.e. before calling 'gcry_check_version'.
+
+ 'GCRYCTL_REINIT_SYSCALL_CLAMP; Arguments: none'
+
+ Libgcrypt wraps blocking system calls with two functions calls
+ ("system call clamp") to give user land threading libraries a
+ hook for re-scheduling. This works by reading the system call
+ clamp from Libgpg-error at initialization time. However
+ sometimes Libgcrypt needs to be initialized before the user
+ land threading systems and at that point the system call clamp
+ has not been registered with Libgpg-error and in turn
+ Libgcrypt would not use them. The control code can be used to
+ tell Libgcrypt that a system call clamp has now been
+ registered with Libgpg-error and advised it to read the clamp
+ again. Obviously this control code may only be used before a
+ second thread is started in a process.
+
+\1f
+File: gcrypt.info, Node: Error Handling, Prev: Controlling the library, Up: Generalities
+
+3.2 Error Handling
+==================
+
+Many functions in Libgcrypt can return an error if they fail. For this
+reason, the application should always catch the error condition and take
+appropriate measures, for example by releasing the resources and passing
+the error up to the caller, or by displaying a descriptive message to
+the user and cancelling the operation.
+
+ Some error values do not indicate a system error or an error in the
+operation, but the result of an operation that failed properly. For
+example, if you try to decrypt a tempered message, the decryption will
+fail. Another error value actually means that the end of a data buffer
+or list has been reached. The following descriptions explain for many
+error codes what they mean usually. Some error values have specific
+meanings if returned by a certain functions. Such cases are described
+in the documentation of those functions.
+
+ Libgcrypt uses the 'libgpg-error' library. This allows to share the
+error codes with other components of the GnuPG system, and to pass error
+values transparently from the crypto engine, or some helper application
+of the crypto engine, to the user. This way no information is lost. As
+a consequence, Libgcrypt does not use its own identifiers for error
+codes, but uses those provided by 'libgpg-error'. They usually start
+with 'GPG_ERR_'.
+
+ However, Libgcrypt does provide aliases for the functions defined in
+libgpg-error, which might be preferred for name space consistency.
+
+ Most functions in Libgcrypt return an error code in the case of
+failure. For this reason, the application should always catch the error
+condition and take appropriate measures, for example by releasing the
+resources and passing the error up to the caller, or by displaying a
+descriptive message to the user and canceling the operation.
+
+ Some error values do not indicate a system error or an error in the
+operation, but the result of an operation that failed properly.
+
+ GnuPG components, including Libgcrypt, use an extra library named
+libgpg-error to provide a common error handling scheme. For more
+information on libgpg-error, see the according manual.
+
+* Menu:
+
+* Error Values:: The error value and what it means.
+* Error Sources:: A list of important error sources.
+* Error Codes:: A list of important error codes.
+* Error Strings:: How to get a descriptive string from a value.
+
+\1f
+File: gcrypt.info, Node: Error Values, Next: Error Sources, Up: Error Handling
+
+3.2.1 Error Values
+------------------
+
+ -- Data type: gcry_err_code_t
+ The 'gcry_err_code_t' type is an alias for the 'libgpg-error' type
+ 'gpg_err_code_t'. The error code indicates the type of an error,
+ or the reason why an operation failed.
+
+ A list of important error codes can be found in the next section.
+
+ -- Data type: gcry_err_source_t
+ The 'gcry_err_source_t' type is an alias for the 'libgpg-error'
+ type 'gpg_err_source_t'. The error source has not a precisely
+ defined meaning. Sometimes it is the place where the error
+ happened, sometimes it is the place where an error was encoded into
+ an error value. Usually the error source will give an indication
+ to where to look for the problem. This is not always true, but it
+ is attempted to achieve this goal.
+
+ A list of important error sources can be found in the next section.
+
+ -- Data type: gcry_error_t
+ The 'gcry_error_t' type is an alias for the 'libgpg-error' type
+ 'gpg_error_t'. An error value like this has always two components,
+ an error code and an error source. Both together form the error
+ value.
+
+ Thus, the error value can not be directly compared against an error
+ code, but the accessor functions described below must be used.
+ However, it is guaranteed that only 0 is used to indicate success
+ ('GPG_ERR_NO_ERROR'), and that in this case all other parts of the
+ error value are set to 0, too.
+
+ Note that in Libgcrypt, the error source is used purely for
+ diagnostic purposes. Only the error code should be checked to test
+ for a certain outcome of a function. The manual only documents the
+ error code part of an error value. The error source is left
+ unspecified and might be anything.
+
+ -- Function: gcry_err_code_t gcry_err_code (gcry_error_t ERR)
+ The static inline function 'gcry_err_code' returns the
+ 'gcry_err_code_t' component of the error value ERR. This function
+ must be used to extract the error code from an error value in order
+ to compare it with the 'GPG_ERR_*' error code macros.
+
+ -- Function: gcry_err_source_t gcry_err_source (gcry_error_t ERR)
+ The static inline function 'gcry_err_source' returns the
+ 'gcry_err_source_t' component of the error value ERR. This
+ function must be used to extract the error source from an error
+ value in order to compare it with the 'GPG_ERR_SOURCE_*' error
+ source macros.
+
+ -- Function: gcry_error_t gcry_err_make (gcry_err_source_t SOURCE,
+ gcry_err_code_t CODE)
+ The static inline function 'gcry_err_make' returns the error value
+ consisting of the error source SOURCE and the error code CODE.
+
+ This function can be used in callback functions to construct an
+ error value to return it to the library.
+
+ -- Function: gcry_error_t gcry_error (gcry_err_code_t CODE)
+ The static inline function 'gcry_error' returns the error value
+ consisting of the default error source and the error code CODE.
+
+ For GCRY applications, the default error source is
+ 'GPG_ERR_SOURCE_USER_1'. You can define 'GCRY_ERR_SOURCE_DEFAULT'
+ before including 'gcrypt.h' to change this default.
+
+ This function can be used in callback functions to construct an
+ error value to return it to the library.
+
+ The 'libgpg-error' library provides error codes for all system error
+numbers it knows about. If ERR is an unknown error number, the error
+code 'GPG_ERR_UNKNOWN_ERRNO' is used. The following functions can be
+used to construct error values from system errno numbers.
+
+ -- Function: gcry_error_t gcry_err_make_from_errno
+ (gcry_err_source_t SOURCE, int ERR)
+ The function 'gcry_err_make_from_errno' is like 'gcry_err_make',
+ but it takes a system error like 'errno' instead of a
+ 'gcry_err_code_t' error code.
+
+ -- Function: gcry_error_t gcry_error_from_errno (int ERR)
+ The function 'gcry_error_from_errno' is like 'gcry_error', but it
+ takes a system error like 'errno' instead of a 'gcry_err_code_t'
+ error code.
+
+ Sometimes you might want to map system error numbers to error codes
+directly, or map an error code representing a system error back to the
+system error number. The following functions can be used to do that.
+
+ -- Function: gcry_err_code_t gcry_err_code_from_errno (int ERR)
+ The function 'gcry_err_code_from_errno' returns the error code for
+ the system error ERR. If ERR is not a known system error, the
+ function returns 'GPG_ERR_UNKNOWN_ERRNO'.
+
+ -- Function: int gcry_err_code_to_errno (gcry_err_code_t ERR)
+ The function 'gcry_err_code_to_errno' returns the system error for
+ the error code ERR. If ERR is not an error code representing a
+ system error, or if this system error is not defined on this
+ system, the function returns '0'.
+
+\1f
+File: gcrypt.info, Node: Error Sources, Next: Error Codes, Prev: Error Values, Up: Error Handling
+
+3.2.2 Error Sources
+-------------------
+
+The library 'libgpg-error' defines an error source for every component
+of the GnuPG system. The error source part of an error value is not
+well defined. As such it is mainly useful to improve the diagnostic
+error message for the user.
+
+ If the error code part of an error value is '0', the whole error
+value will be '0'. In this case the error source part is of course
+'GPG_ERR_SOURCE_UNKNOWN'.
+
+ The list of error sources that might occur in applications using
+Libgcrypt is:
+
+'GPG_ERR_SOURCE_UNKNOWN'
+ The error source is not known. The value of this error source is
+ '0'.
+
+'GPG_ERR_SOURCE_GPGME'
+ The error source is GPGME itself.
+
+'GPG_ERR_SOURCE_GPG'
+ The error source is GnuPG, which is the crypto engine used for the
+ OpenPGP protocol.
+
+'GPG_ERR_SOURCE_GPGSM'
+ The error source is GPGSM, which is the crypto engine used for the
+ OpenPGP protocol.
+
+'GPG_ERR_SOURCE_GCRYPT'
+ The error source is 'libgcrypt', which is used by crypto engines to
+ perform cryptographic operations.
+
+'GPG_ERR_SOURCE_GPGAGENT'
+ The error source is 'gpg-agent', which is used by crypto engines to
+ perform operations with the secret key.
+
+'GPG_ERR_SOURCE_PINENTRY'
+ The error source is 'pinentry', which is used by 'gpg-agent' to
+ query the passphrase to unlock a secret key.
+
+'GPG_ERR_SOURCE_SCD'
+ The error source is the SmartCard Daemon, which is used by
+ 'gpg-agent' to delegate operations with the secret key to a
+ SmartCard.
+
+'GPG_ERR_SOURCE_KEYBOX'
+ The error source is 'libkbx', a library used by the crypto engines
+ to manage local keyrings.
+
+'GPG_ERR_SOURCE_USER_1'
+'GPG_ERR_SOURCE_USER_2'
+'GPG_ERR_SOURCE_USER_3'
+'GPG_ERR_SOURCE_USER_4'
+ These error sources are not used by any GnuPG component and can be
+ used by other software. For example, applications using Libgcrypt
+ can use them to mark error values coming from callback handlers.
+ Thus 'GPG_ERR_SOURCE_USER_1' is the default for errors created with
+ 'gcry_error' and 'gcry_error_from_errno', unless you define
+ 'GCRY_ERR_SOURCE_DEFAULT' before including 'gcrypt.h'.
+
+\1f
+File: gcrypt.info, Node: Error Codes, Next: Error Strings, Prev: Error Sources, Up: Error Handling
+
+3.2.3 Error Codes
+-----------------
+
+The library 'libgpg-error' defines many error values. The following
+list includes the most important error codes.
+
+'GPG_ERR_EOF'
+ This value indicates the end of a list, buffer or file.
+
+'GPG_ERR_NO_ERROR'
+ This value indicates success. The value of this error code is '0'.
+ Also, it is guaranteed that an error value made from the error code
+ '0' will be '0' itself (as a whole). This means that the error
+ source information is lost for this error code, however, as this
+ error code indicates that no error occurred, this is generally not
+ a problem.
+
+'GPG_ERR_GENERAL'
+ This value means that something went wrong, but either there is not
+ enough information about the problem to return a more useful error
+ value, or there is no separate error value for this type of
+ problem.
+
+'GPG_ERR_ENOMEM'
+ This value means that an out-of-memory condition occurred.
+
+'GPG_ERR_E...'
+ System errors are mapped to GPG_ERR_EFOO where FOO is the symbol
+ for the system error.
+
+'GPG_ERR_INV_VALUE'
+ This value means that some user provided data was out of range.
+
+'GPG_ERR_UNUSABLE_PUBKEY'
+ This value means that some recipients for a message were invalid.
+
+'GPG_ERR_UNUSABLE_SECKEY'
+ This value means that some signers were invalid.
+
+'GPG_ERR_NO_DATA'
+ This value means that data was expected where no data was found.
+
+'GPG_ERR_CONFLICT'
+ This value means that a conflict of some sort occurred.
+
+'GPG_ERR_NOT_IMPLEMENTED'
+ This value indicates that the specific function (or operation) is
+ not implemented. This error should never happen. It can only
+ occur if you use certain values or configuration options which do
+ not work, but for which we think that they should work at some
+ later time.
+
+'GPG_ERR_DECRYPT_FAILED'
+ This value indicates that a decryption operation was unsuccessful.
+
+'GPG_ERR_WRONG_KEY_USAGE'
+ This value indicates that a key is not used appropriately.
+
+'GPG_ERR_NO_SECKEY'
+ This value indicates that no secret key for the user ID is
+ available.
+
+'GPG_ERR_UNSUPPORTED_ALGORITHM'
+ This value means a verification failed because the cryptographic
+ algorithm is not supported by the crypto backend.
+
+'GPG_ERR_BAD_SIGNATURE'
+ This value means a verification failed because the signature is
+ bad.
+
+'GPG_ERR_NO_PUBKEY'
+ This value means a verification failed because the public key is
+ not available.
+
+'GPG_ERR_NOT_OPERATIONAL'
+ This value means that the library is not yet in state which allows
+ to use this function. This error code is in particular returned if
+ Libgcrypt is operated in FIPS mode and the internal state of the
+ library does not yet or not anymore allow the use of a service.
+
+ This error code is only available with newer libgpg-error versions,
+ thus you might see "invalid error code" when passing this to
+ 'gpg_strerror'. The numeric value of this error code is 176.
+
+'GPG_ERR_USER_1'
+'GPG_ERR_USER_2'
+'...'
+'GPG_ERR_USER_16'
+ These error codes are not used by any GnuPG component and can be
+ freely used by other software. Applications using Libgcrypt might
+ use them to mark specific errors returned by callback handlers if
+ no suitable error codes (including the system errors) for these
+ errors exist already.
+
+\1f
+File: gcrypt.info, Node: Error Strings, Prev: Error Codes, Up: Error Handling
+
+3.2.4 Error Strings
+-------------------
+
+ -- Function: const char * gcry_strerror (gcry_error_t ERR)
+ The function 'gcry_strerror' returns a pointer to a statically
+ allocated string containing a description of the error code
+ contained in the error value ERR. This string can be used to
+ output a diagnostic message to the user.
+
+ -- Function: const char * gcry_strsource (gcry_error_t ERR)
+ The function 'gcry_strsource' returns a pointer to a statically
+ allocated string containing a description of the error source
+ contained in the error value ERR. This string can be used to
+ output a diagnostic message to the user.
+
+ The following example illustrates the use of the functions described
+above:
+
+ {
+ gcry_cipher_hd_t handle;
+ gcry_error_t err = 0;
+
+ err = gcry_cipher_open (&handle, GCRY_CIPHER_AES,
+ GCRY_CIPHER_MODE_CBC, 0);
+ if (err)
+ {
+ fprintf (stderr, "Failure: %s/%s\n",
+ gcry_strsource (err),
+ gcry_strerror (err));
+ }
+ }
+
+\1f
+File: gcrypt.info, Node: Handler Functions, Next: Symmetric cryptography, Prev: Generalities, Up: Top
+
+4 Handler Functions
+*******************
+
+Libgcrypt makes it possible to install so called 'handler functions',
+which get called by Libgcrypt in case of certain events.
+
+* Menu:
+
+* Progress handler:: Using a progress handler function.
+* Allocation handler:: Using special memory allocation functions.
+* Error handler:: Using error handler functions.
+* Logging handler:: Using a special logging function.
+
+\1f
+File: gcrypt.info, Node: Progress handler, Next: Allocation handler, Up: Handler Functions
+
+4.1 Progress handler
+====================
+
+It is often useful to retrieve some feedback while long running
+operations are performed.
+
+ -- Data type: gcry_handler_progress_t
+ Progress handler functions have to be of the type
+ 'gcry_handler_progress_t', which is defined as:
+
+ 'void (*gcry_handler_progress_t) (void *, const char *, int, int,
+ int)'
+
+ The following function may be used to register a handler function for
+this purpose.
+
+ -- Function: void gcry_set_progress_handler (gcry_handler_progress_t
+ CB, void *CB_DATA)
+
+ This function installs CB as the 'Progress handler' function. It
+ may be used only during initialization. CB must be defined as
+ follows:
+
+ void
+ my_progress_handler (void *CB_DATA, const char *WHAT,
+ int PRINTCHAR, int CURRENT, int TOTAL)
+ {
+ /* Do something. */
+ }
+
+ A description of the arguments of the progress handler function
+ follows.
+
+ CB_DATA
+ The argument provided in the call to
+ 'gcry_set_progress_handler'.
+ WHAT
+ A string identifying the type of the progress output. The
+ following values for WHAT are defined:
+
+ 'need_entropy'
+ Not enough entropy is available. TOTAL holds the number
+ of required bytes.
+
+ 'wait_dev_random'
+ Waiting to re-open a random device. TOTAL gives the
+ number of seconds until the next try.
+
+ 'primegen'
+ Values for PRINTCHAR:
+ '\n'
+ Prime generated.
+ '!'
+ Need to refresh the pool of prime numbers.
+ '<, >'
+ Number of bits adjusted.
+ '^'
+ Searching for a generator.
+ '.'
+ Fermat test on 10 candidates failed.
+ ':'
+ Restart with a new random value.
+ '+'
+ Rabin Miller test passed.
+
+\1f
+File: gcrypt.info, Node: Allocation handler, Next: Error handler, Prev: Progress handler, Up: Handler Functions
+
+4.2 Allocation handler
+======================
+
+It is possible to make Libgcrypt use special memory allocation functions
+instead of the built-in ones.
+
+ Memory allocation functions are of the following types:
+ -- Data type: gcry_handler_alloc_t
+ This type is defined as: 'void *(*gcry_handler_alloc_t) (size_t
+ n)'.
+ -- Data type: gcry_handler_secure_check_t
+ This type is defined as: 'int *(*gcry_handler_secure_check_t)
+ (const void *)'.
+ -- Data type: gcry_handler_realloc_t
+ This type is defined as: 'void *(*gcry_handler_realloc_t) (void *p,
+ size_t n)'.
+ -- Data type: gcry_handler_free_t
+ This type is defined as: 'void *(*gcry_handler_free_t) (void *)'.
+
+ Special memory allocation functions can be installed with the
+following function:
+
+ -- Function: void gcry_set_allocation_handler (gcry_handler_alloc_t
+ FUNC_ALLOC, gcry_handler_alloc_t FUNC_ALLOC_SECURE,
+ gcry_handler_secure_check_t FUNC_SECURE_CHECK,
+ gcry_handler_realloc_t FUNC_REALLOC, gcry_handler_free_t
+ FUNC_FREE)
+ Install the provided functions and use them instead of the built-in
+ functions for doing memory allocation. Using this function is in
+ general not recommended because the standard Libgcrypt allocation
+ functions are guaranteed to zeroize memory if needed.
+
+ This function may be used only during initialization and may not be
+ used in fips mode.
+
+\1f
+File: gcrypt.info, Node: Error handler, Next: Logging handler, Prev: Allocation handler, Up: Handler Functions
+
+4.3 Error handler
+=================
+
+The following functions may be used to register handler functions that
+are called by Libgcrypt in case certain error conditions occur. They
+may and should be registered prior to calling 'gcry_check_version'.
+
+ -- Data type: gcry_handler_no_mem_t
+ This type is defined as: 'int (*gcry_handler_no_mem_t) (void *,
+ size_t, unsigned int)'
+ -- Function: void gcry_set_outofcore_handler (gcry_handler_no_mem_t
+ FUNC_NO_MEM, void *CB_DATA)
+ This function registers FUNC_NO_MEM as 'out-of-core handler', which
+ means that it will be called in the case of not having enough
+ memory available. The handler is called with 3 arguments: The
+ first one is the pointer CB_DATA as set with this function, the
+ second is the requested memory size and the last being a flag. If
+ bit 0 of the flag is set, secure memory has been requested. The
+ handler should either return true to indicate that Libgcrypt should
+ try again allocating memory or return false to let Libgcrypt use
+ its default fatal error handler.
+
+ -- Data type: gcry_handler_error_t
+ This type is defined as: 'void (*gcry_handler_error_t) (void *,
+ int, const char *)'
+
+ -- Function: void gcry_set_fatalerror_handler (gcry_handler_error_t
+ FUNC_ERROR, void *CB_DATA)
+ This function registers FUNC_ERROR as 'error handler', which means
+ that it will be called in error conditions.
+
+\1f
+File: gcrypt.info, Node: Logging handler, Prev: Error handler, Up: Handler Functions
+
+4.4 Logging handler
+===================
+
+ -- Data type: gcry_handler_log_t
+ This type is defined as: 'void (*gcry_handler_log_t) (void *, int,
+ const char *, va_list)'
+
+ -- Function: void gcry_set_log_handler (gcry_handler_log_t FUNC_LOG,
+ void *CB_DATA)
+ This function registers FUNC_LOG as 'logging handler', which means
+ that it will be called in case Libgcrypt wants to log a message.
+ This function may and should be used prior to calling
+ 'gcry_check_version'.
+
+\1f
+File: gcrypt.info, Node: Symmetric cryptography, Next: Public Key cryptography, Prev: Handler Functions, Up: Top
+
+5 Symmetric cryptography
+************************
+
+The cipher functions are used for symmetrical cryptography, i.e.
+cryptography using a shared key. The programming model follows an
+open/process/close paradigm and is in that similar to other building
+blocks provided by Libgcrypt.
+
+* Menu:
+
+* Available ciphers:: List of ciphers supported by the library.
+* Available cipher modes:: List of cipher modes supported by the library.
+* Working with cipher handles:: How to perform operations related to cipher handles.
+* General cipher functions:: General cipher functions independent of cipher handles.
+
+\1f
+File: gcrypt.info, Node: Available ciphers, Next: Available cipher modes, Up: Symmetric cryptography
+
+5.1 Available ciphers
+=====================
+
+'GCRY_CIPHER_NONE'
+ This is not a real algorithm but used by some functions as error
+ return. The value always evaluates to false.
+
+'GCRY_CIPHER_IDEA'
+ This is the IDEA algorithm.
+
+'GCRY_CIPHER_3DES'
+ Triple-DES with 3 Keys as EDE. The key size of this algorithm is
+ 168 but you have to pass 192 bits because the most significant bits
+ of each byte are ignored.
+
+'GCRY_CIPHER_CAST5'
+ CAST128-5 block cipher algorithm. The key size is 128 bits.
+
+'GCRY_CIPHER_BLOWFISH'
+ The blowfish algorithm. The current implementation allows only for
+ a key size of 128 bits.
+
+'GCRY_CIPHER_SAFER_SK128'
+ Reserved and not currently implemented.
+
+'GCRY_CIPHER_DES_SK'
+ Reserved and not currently implemented.
+
+'GCRY_CIPHER_AES'
+'GCRY_CIPHER_AES128'
+'GCRY_CIPHER_RIJNDAEL'
+'GCRY_CIPHER_RIJNDAEL128'
+ AES (Rijndael) with a 128 bit key.
+
+'GCRY_CIPHER_AES192'
+'GCRY_CIPHER_RIJNDAEL192'
+ AES (Rijndael) with a 192 bit key.
+
+'GCRY_CIPHER_AES256'
+'GCRY_CIPHER_RIJNDAEL256'
+ AES (Rijndael) with a 256 bit key.
+
+'GCRY_CIPHER_TWOFISH'
+ The Twofish algorithm with a 256 bit key.
+
+'GCRY_CIPHER_TWOFISH128'
+ The Twofish algorithm with a 128 bit key.
+
+'GCRY_CIPHER_ARCFOUR'
+ An algorithm which is 100% compatible with RSA Inc.'s RC4
+ algorithm. Note that this is a stream cipher and must be used very
+ carefully to avoid a couple of weaknesses.
+
+'GCRY_CIPHER_DES'
+ Standard DES with a 56 bit key. You need to pass 64 bit but the
+ high bits of each byte are ignored. Note, that this is a weak
+ algorithm which can be broken in reasonable time using a brute
+ force approach.
+
+'GCRY_CIPHER_SERPENT128'
+'GCRY_CIPHER_SERPENT192'
+'GCRY_CIPHER_SERPENT256'
+ The Serpent cipher from the AES contest.
+
+'GCRY_CIPHER_RFC2268_40'
+'GCRY_CIPHER_RFC2268_128'
+ Ron's Cipher 2 in the 40 and 128 bit variants.
+
+'GCRY_CIPHER_SEED'
+ A 128 bit cipher as described by RFC4269.
+
+'GCRY_CIPHER_CAMELLIA128'
+'GCRY_CIPHER_CAMELLIA192'
+'GCRY_CIPHER_CAMELLIA256'
+ The Camellia cipher by NTT. See
+ <http://info.isl.ntt.co.jp/crypt/eng/camellia/specifications.html>.
+
+'GCRY_CIPHER_SALSA20'
+ This is the Salsa20 stream cipher.
+
+'GCRY_CIPHER_SALSA20R12'
+ This is the Salsa20/12 - reduced round version of Salsa20 stream
+ cipher.
+
+'GCRY_CIPHER_GOST28147'
+ The GOST 28147-89 cipher, defined in the respective GOST standard.
+ Translation of this GOST into English is provided in the RFC-5830.
+
+'GCRY_CIPHER_CHACHA20'
+ This is the ChaCha20 stream cipher.
+
+\1f
+File: gcrypt.info, Node: Available cipher modes, Next: Working with cipher handles, Prev: Available ciphers, Up: Symmetric cryptography
+
+5.2 Available cipher modes
+==========================
+
+'GCRY_CIPHER_MODE_NONE'
+ No mode specified. This should not be used. The only exception is
+ that if Libgcrypt is not used in FIPS mode and if any debug flag
+ has been set, this mode may be used to bypass the actual
+ encryption.
+
+'GCRY_CIPHER_MODE_ECB'
+ Electronic Codebook mode.
+
+'GCRY_CIPHER_MODE_CFB'
+'GCRY_CIPHER_MODE_CFB8'
+ Cipher Feedback mode. For GCRY_CIPHER_MODE_CFB the shift size
+ equals the block size of the cipher (e.g. for AES it is CFB-128).
+ For GCRY_CIPHER_MODE_CFB8 the shift size is 8 bit but that variant
+ is not yet available.
+
+'GCRY_CIPHER_MODE_CBC'
+ Cipher Block Chaining mode.
+
+'GCRY_CIPHER_MODE_STREAM'
+ Stream mode, only to be used with stream cipher algorithms.
+
+'GCRY_CIPHER_MODE_OFB'
+ Output Feedback mode.
+
+'GCRY_CIPHER_MODE_CTR'
+ Counter mode.
+
+'GCRY_CIPHER_MODE_AESWRAP'
+ This mode is used to implement the AES-Wrap algorithm according to
+ RFC-3394. It may be used with any 128 bit block length algorithm,
+ however the specs require one of the 3 AES algorithms. These
+ special conditions apply: If 'gcry_cipher_setiv' has not been used
+ the standard IV is used; if it has been used the lower 64 bit of
+ the IV are used as the Alternative Initial Value. On encryption
+ the provided output buffer must be 64 bit (8 byte) larger than the
+ input buffer; in-place encryption is still allowed. On decryption
+ the output buffer may be specified 64 bit (8 byte) shorter than
+ then input buffer. As per specs the input length must be at least
+ 128 bits and the length must be a multiple of 64 bits.
+
+'GCRY_CIPHER_MODE_CCM'
+ Counter with CBC-MAC mode is an Authenticated Encryption with
+ Associated Data (AEAD) block cipher mode, which is specified in
+ 'NIST Special Publication 800-38C' and RFC 3610.
+
+'GCRY_CIPHER_MODE_GCM'
+ Galois/Counter Mode (GCM) is an Authenticated Encryption with
+ Associated Data (AEAD) block cipher mode, which is specified in
+ 'NIST Special Publication 800-38D'.
+
+'GCRY_CIPHER_MODE_POLY1305'
+ This mode implements the Poly1305 Authenticated Encryption with
+ Associated Data (AEAD) mode according to RFC-7539. This mode can
+ be used with ChaCha20 stream cipher.
+
+'GCRY_CIPHER_MODE_OCB'
+ OCB is an Authenticated Encryption with Associated Data (AEAD)
+ block cipher mode, which is specified in RFC-7253. Supported tag
+ lengths are 128, 96, and 64 bit with the default being 128 bit. To
+ switch to a different tag length 'gcry_cipher_ctl' using the
+ command 'GCRYCTL_SET_TAGLEN' and the address of an 'int' variable
+ set to 12 (for 96 bit) or 8 (for 64 bit) provided for the 'buffer'
+ argument and 'sizeof(int)' for 'buflen'.
+
+ Note that the use of 'gcry_cipher_final' is required.
+
+'GCRY_CIPHER_MODE_XTS'
+ XEX-based tweaked-codebook mode with ciphertext stealing (XTS) mode
+ is used to implement the AES-XTS as specified in IEEE 1619 Standard
+ Architecture for Encrypted Shared Storage Media and NIST SP800-38E.
+
+ The XTS mode requires doubling key-length, for example, using
+ 512-bit key with AES-256 ('GCRY_CIPHER_AES256'). The 128-bit tweak
+ value is feed to XTS mode as little-endian byte array using
+ 'gcry_cipher_setiv' function. When encrypting or decrypting,
+ full-sized data unit buffers needs to be passed to
+ 'gcry_cipher_encrypt' or 'gcry_cipher_decrypt'. The tweak value is
+ automatically incremented after each call of 'gcry_cipher_encrypt'
+ and 'gcry_cipher_decrypt'. Auto-increment allows avoiding need of
+ setting IV between processing of sequential data units.
+
+\1f
+File: gcrypt.info, Node: Working with cipher handles, Next: General cipher functions, Prev: Available cipher modes, Up: Symmetric cryptography
+
+5.3 Working with cipher handles
+===============================
+
+To use a cipher algorithm, you must first allocate an according handle.
+This is to be done using the open function:
+
+ -- Function: gcry_error_t gcry_cipher_open (gcry_cipher_hd_t *HD, int
+ ALGO, int MODE, unsigned int FLAGS)
+
+ This function creates the context handle required for most of the
+ other cipher functions and returns a handle to it in 'hd'. In case
+ of an error, an according error code is returned.
+
+ The ID of algorithm to use must be specified via ALGO. See *note
+ Available ciphers::, for a list of supported ciphers and the
+ according constants.
+
+ Besides using the constants directly, the function
+ 'gcry_cipher_map_name' may be used to convert the textual name of
+ an algorithm into the according numeric ID.
+
+ The cipher mode to use must be specified via MODE. See *note
+ Available cipher modes::, for a list of supported cipher modes and
+ the according constants. Note that some modes are incompatible
+ with some algorithms - in particular, stream mode
+ ('GCRY_CIPHER_MODE_STREAM') only works with stream ciphers.
+ Poly1305 AEAD mode ('GCRY_CIPHER_MODE_POLY1305') only works with
+ ChaCha20 stream cipher. The block cipher modes
+ ('GCRY_CIPHER_MODE_ECB', 'GCRY_CIPHER_MODE_CBC',
+ 'GCRY_CIPHER_MODE_CFB', 'GCRY_CIPHER_MODE_OFB' and
+ 'GCRY_CIPHER_MODE_CTR') will work with any block cipher algorithm.
+ GCM mode ('GCRY_CIPHER_MODE_CCM'), CCM mode
+ ('GCRY_CIPHER_MODE_GCM'), OCB mode ('GCRY_CIPHER_MODE_OCB'), and
+ XTS mode ('GCRY_CIPHER_MODE_XTS') will only work with block cipher
+ algorithms which have the block size of 16 bytes.
+
+ The third argument FLAGS can either be passed as '0' or as the
+ bit-wise OR of the following constants.
+
+ 'GCRY_CIPHER_SECURE'
+ Make sure that all operations are allocated in secure memory.
+ This is useful when the key material is highly confidential.
+ 'GCRY_CIPHER_ENABLE_SYNC'
+ This flag enables the CFB sync mode, which is a special
+ feature of Libgcrypt's CFB mode implementation to allow for
+ OpenPGP's CFB variant. See 'gcry_cipher_sync'.
+ 'GCRY_CIPHER_CBC_CTS'
+ Enable cipher text stealing (CTS) for the CBC mode. Cannot be
+ used simultaneous as GCRY_CIPHER_CBC_MAC. CTS mode makes it
+ possible to transform data of almost arbitrary size (only
+ limitation is that it must be greater than the algorithm's
+ block size).
+ 'GCRY_CIPHER_CBC_MAC'
+ Compute CBC-MAC keyed checksums. This is the same as CBC
+ mode, but only output the last block. Cannot be used
+ simultaneous as GCRY_CIPHER_CBC_CTS.
+
+ Use the following function to release an existing handle:
+
+ -- Function: void gcry_cipher_close (gcry_cipher_hd_t H)
+
+ This function releases the context created by 'gcry_cipher_open'.
+ It also zeroises all sensitive information associated with this
+ cipher handle.
+
+ In order to use a handle for performing cryptographic operations, a
+'key' has to be set first:
+
+ -- Function: gcry_error_t gcry_cipher_setkey (gcry_cipher_hd_t H, const
+ void *K, size_t L)
+
+ Set the key K used for encryption or decryption in the context
+ denoted by the handle H. The length L (in bytes) of the key K must
+ match the required length of the algorithm set for this context or
+ be in the allowed range for algorithms with variable key size. The
+ function checks this and returns an error if there is a problem. A
+ caller should always check for an error.
+
+ Most crypto modes requires an initialization vector (IV), which
+usually is a non-secret random string acting as a kind of salt value.
+The CTR mode requires a counter, which is also similar to a salt value.
+To set the IV or CTR, use these functions:
+
+ -- Function: gcry_error_t gcry_cipher_setiv (gcry_cipher_hd_t H, const
+ void *K, size_t L)
+
+ Set the initialization vector used for encryption or decryption.
+ The vector is passed as the buffer K of length L bytes and copied
+ to internal data structures. The function checks that the IV
+ matches the requirement of the selected algorithm and mode.
+
+ This function is also used by AEAD modes and with Salsa20 and
+ ChaCha20 stream ciphers to set or update the required nonce. In
+ these cases it needs to be called after setting the key.
+
+ -- Function: gcry_error_t gcry_cipher_setctr (gcry_cipher_hd_t H, const
+ void *C, size_t L)
+
+ Set the counter vector used for encryption or decryption. The
+ counter is passed as the buffer C of length L bytes and copied to
+ internal data structures. The function checks that the counter
+ matches the requirement of the selected algorithm (i.e., it must be
+ the same size as the block size).
+
+ -- Function: gcry_error_t gcry_cipher_reset (gcry_cipher_hd_t H)
+
+ Set the given handle's context back to the state it had after the
+ last call to gcry_cipher_setkey and clear the initialization
+ vector.
+
+ Note that gcry_cipher_reset is implemented as a macro.
+
+ Authenticated Encryption with Associated Data (AEAD) block cipher
+modes require the handling of the authentication tag and the additional
+authenticated data, which can be done by using the following functions:
+
+ -- Function: gcry_error_t gcry_cipher_authenticate (gcry_cipher_hd_t H,
+ const void *ABUF, size_t ABUFLEN)
+
+ Process the buffer ABUF of length ABUFLEN as the additional
+ authenticated data (AAD) for AEAD cipher modes.
+
+ -- Function: gcry_error_t gcry_cipher_gettag (gcry_cipher_hd_t H,
+ void *TAG, size_t TAGLEN)
+
+ This function is used to read the authentication tag after
+ encryption. The function finalizes and outputs the authentication
+ tag to the buffer TAG of length TAGLEN bytes.
+
+ Depending on the used mode certain restrictions for TAGLEN are
+ enforced: For GCM TAGLEN must be at least 16 or one of the allowed
+ truncated lengths (4, 8, 12, 13, 14, or 15).
+
+ -- Function: gcry_error_t gcry_cipher_checktag (gcry_cipher_hd_t H,
+ const void *TAG, size_t TAGLEN)
+
+ Check the authentication tag after decryption. The authentication
+ tag is passed as the buffer TAG of length TAGLEN bytes and compared
+ to internal authentication tag computed during decryption. Error
+ code 'GPG_ERR_CHECKSUM' is returned if the authentication tag in
+ the buffer TAG does not match the authentication tag calculated
+ during decryption.
+
+ Depending on the used mode certain restrictions for TAGLEN are
+ enforced: For GCM TAGLEN must either be 16 or one of the allowed
+ truncated lengths (4, 8, 12, 13, 14, or 15).
+
+ The actual encryption and decryption is done by using one of the
+following functions. They may be used as often as required to process
+all the data.
+
+ -- Function: gcry_error_t gcry_cipher_encrypt (gcry_cipher_hd_t H,
+ unsigned char *out, size_t OUTSIZE, const unsigned char *IN,
+ size_t INLEN)
+
+ 'gcry_cipher_encrypt' is used to encrypt the data. This function
+ can either work in place or with two buffers. It uses the cipher
+ context already setup and described by the handle H. There are 2
+ ways to use the function: If IN is passed as 'NULL' and INLEN is
+ '0', in-place encryption of the data in OUT of length OUTSIZE takes
+ place. With IN being not 'NULL', INLEN bytes are encrypted to the
+ buffer OUT which must have at least a size of INLEN. OUTSIZE must
+ be set to the allocated size of OUT, so that the function can check
+ that there is sufficient space. Note that overlapping buffers are
+ not allowed.
+
+ Depending on the selected algorithms and encryption mode, the
+ length of the buffers must be a multiple of the block size.
+
+ Some encryption modes require that 'gcry_cipher_final' is used
+ before the final data chunk is passed to this function.
+
+ The function returns '0' on success or an error code.
+
+ -- Function: gcry_error_t gcry_cipher_decrypt (gcry_cipher_hd_t H,
+ unsigned char *out, size_t OUTSIZE, const unsigned char *IN,
+ size_t INLEN)
+
+ 'gcry_cipher_decrypt' is used to decrypt the data. This function
+ can either work in place or with two buffers. It uses the cipher
+ context already setup and described by the handle H. There are 2
+ ways to use the function: If IN is passed as 'NULL' and INLEN is
+ '0', in-place decryption of the data in OUT or length OUTSIZE takes
+ place. With IN being not 'NULL', INLEN bytes are decrypted to the
+ buffer OUT which must have at least a size of INLEN. OUTSIZE must
+ be set to the allocated size of OUT, so that the function can check
+ that there is sufficient space. Note that overlapping buffers are
+ not allowed.
+
+ Depending on the selected algorithms and encryption mode, the
+ length of the buffers must be a multiple of the block size.
+
+ Some encryption modes require that 'gcry_cipher_final' is used
+ before the final data chunk is passed to this function.
+
+ The function returns '0' on success or an error code.
+
+ The OCB mode features integrated padding and must thus be told about
+the end of the input data. This is done with:
+
+ -- Function: gcry_error_t gcry_cipher_final (gcry_cipher_hd_t H)
+
+ Set a flag in the context to tell the encrypt and decrypt functions
+ that their next call will provide the last chunk of data. Only the
+ first call to this function has an effect and only for modes which
+ support it. Checking the error is in general not necessary. This
+ is implemented as a macro.
+
+ OpenPGP (as defined in RFC-4880) requires a special sync operation in
+some places. The following function is used for this:
+
+ -- Function: gcry_error_t gcry_cipher_sync (gcry_cipher_hd_t H)
+
+ Perform the OpenPGP sync operation on context H. Note that this is
+ a no-op unless the context was created with the flag
+ 'GCRY_CIPHER_ENABLE_SYNC'
+
+ Some of the described functions are implemented as macros utilizing a
+catch-all control function. This control function is rarely used
+directly but there is nothing which would inhibit it:
+
+ -- Function: gcry_error_t gcry_cipher_ctl (gcry_cipher_hd_t H, int CMD,
+ void *BUFFER, size_t BUFLEN)
+
+ 'gcry_cipher_ctl' controls various aspects of the cipher module and
+ specific cipher contexts. Usually some more specialized functions
+ or macros are used for this purpose. The semantics of the function
+ and its parameters depends on the the command CMD and the passed
+ context handle H. Please see the comments in the source code
+ ('src/global.c') for details.
+
+ -- Function: gcry_error_t gcry_cipher_info (gcry_cipher_hd_t H, int
+ WHAT, void *BUFFER, size_t *NBYTES)
+
+ 'gcry_cipher_info' is used to retrieve various information about a
+ cipher context or the cipher module in general.
+
+ 'GCRYCTL_GET_TAGLEN:'
+ Return the length of the tag for an AE algorithm mode. An
+ error is returned for modes which do not support a tag.
+ BUFFER must be given as NULL. On success the result is stored
+ NBYTES. The taglen is returned in bytes.
+
+\1f
+File: gcrypt.info, Node: General cipher functions, Prev: Working with cipher handles, Up: Symmetric cryptography
+
+5.4 General cipher functions
+============================
+
+To work with the algorithms, several functions are available to map
+algorithm names to the internal identifiers, as well as ways to retrieve
+information about an algorithm or the current cipher context.
+
+ -- Function: gcry_error_t gcry_cipher_algo_info (int ALGO, int WHAT,
+ void *BUFFER, size_t *NBYTES)
+
+ This function is used to retrieve information on a specific
+ algorithm. You pass the cipher algorithm ID as ALGO and the type
+ of information requested as WHAT. The result is either returned as
+ the return code of the function or copied to the provided BUFFER
+ whose allocated length must be available in an integer variable
+ with the address passed in NBYTES. This variable will also receive
+ the actual used length of the buffer.
+
+ Here is a list of supported codes for WHAT:
+
+ 'GCRYCTL_GET_KEYLEN:'
+ Return the length of the key. If the algorithm supports
+ multiple key lengths, the maximum supported value is returned.
+ The length is returned as number of octets (bytes) and not as
+ number of bits in NBYTES; BUFFER must be zero. Note that it
+ is usually better to use the convenience function
+ 'gcry_cipher_get_algo_keylen'.
+
+ 'GCRYCTL_GET_BLKLEN:'
+ Return the block length of the algorithm. The length is
+ returned as a number of octets in NBYTES; BUFFER must be zero.
+ Note that it is usually better to use the convenience function
+ 'gcry_cipher_get_algo_blklen'.
+
+ 'GCRYCTL_TEST_ALGO:'
+ Returns '0' when the specified algorithm is available for use.
+ BUFFER and NBYTES must be zero.
+
+ -- Function: size_t gcry_cipher_get_algo_keylen (ALGO)
+
+ This function returns length of the key for algorithm ALGO. If the
+ algorithm supports multiple key lengths, the maximum supported key
+ length is returned. On error '0' is returned. The key length is
+ returned as number of octets.
+
+ This is a convenience functions which should be preferred over
+ 'gcry_cipher_algo_info' because it allows for proper type checking.
+
+ -- Function: size_t gcry_cipher_get_algo_blklen (int ALGO)
+
+ This functions returns the block-length of the algorithm ALGO
+ counted in octets. On error '0' is returned.
+
+ This is a convenience functions which should be preferred over
+ 'gcry_cipher_algo_info' because it allows for proper type checking.
+
+ -- Function: const char * gcry_cipher_algo_name (int ALGO)
+
+ 'gcry_cipher_algo_name' returns a string with the name of the
+ cipher algorithm ALGO. If the algorithm is not known or another
+ error occurred, the string '"?"' is returned. This function should
+ not be used to test for the availability of an algorithm.
+
+ -- Function: int gcry_cipher_map_name (const char *NAME)
+
+ 'gcry_cipher_map_name' returns the algorithm identifier for the
+ cipher algorithm described by the string NAME. If this algorithm
+ is not available '0' is returned.
+
+ -- Function: int gcry_cipher_mode_from_oid (const char *STRING)
+
+ Return the cipher mode associated with an ASN.1 object identifier.
+ The object identifier is expected to be in the IETF-style dotted
+ decimal notation. The function returns '0' for an unknown object
+ identifier or when no mode is associated with it.
+
+\1f
+File: gcrypt.info, Node: Public Key cryptography, Next: Hashing, Prev: Symmetric cryptography, Up: Top
+
+6 Public Key cryptography
+*************************
+
+Public key cryptography, also known as asymmetric cryptography, is an
+easy way for key management and to provide digital signatures.
+Libgcrypt provides two completely different interfaces to public key
+cryptography, this chapter explains the one based on S-expressions.
+
+* Menu:
+
+* Available algorithms:: Algorithms supported by the library.
+* Used S-expressions:: Introduction into the used S-expression.
+* Cryptographic Functions:: Functions for performing the cryptographic actions.
+* General public-key related Functions:: General functions, not implementing any cryptography.
+
+\1f
+File: gcrypt.info, Node: Available algorithms, Next: Used S-expressions, Up: Public Key cryptography
+
+6.1 Available algorithms
+========================
+
+Libgcrypt supports the RSA (Rivest-Shamir-Adleman) algorithms as well as
+DSA (Digital Signature Algorithm) and Elgamal. The versatile interface
+allows to add more algorithms in the future.
+
+\1f
+File: gcrypt.info, Node: Used S-expressions, Next: Cryptographic Functions, Prev: Available algorithms, Up: Public Key cryptography
+
+6.2 Used S-expressions
+======================
+
+Libgcrypt's API for asymmetric cryptography is based on data structures
+called S-expressions (see
+<http://people.csail.mit.edu/rivest/sexp.html>) and does not work with
+contexts as most of the other building blocks of Libgcrypt do.
+
+The following information are stored in S-expressions:
+
+ * keys
+
+ * plain text data
+
+ * encrypted data
+
+ * signatures
+
+To describe how Libgcrypt expect keys, we use examples. Note that words
+in uppercase indicate parameters whereas lowercase words are literals.
+
+ Note that all MPI (multi-precision-integers) values are expected to
+be in 'GCRYMPI_FMT_USG' format. An easy way to create S-expressions is
+by using 'gcry_sexp_build' which allows to pass a string with
+printf-like escapes to insert MPI values.
+
+* Menu:
+
+* RSA key parameters:: Parameters used with an RSA key.
+* DSA key parameters:: Parameters used with a DSA key.
+* ECC key parameters:: Parameters used with ECC keys.
+
+\1f
+File: gcrypt.info, Node: RSA key parameters, Next: DSA key parameters, Up: Used S-expressions
+
+6.2.1 RSA key parameters
+------------------------
+
+An RSA private key is described by this S-expression:
+
+ (private-key
+ (rsa
+ (n N-MPI)
+ (e E-MPI)
+ (d D-MPI)
+ (p P-MPI)
+ (q Q-MPI)
+ (u U-MPI)))
+
+An RSA public key is described by this S-expression:
+
+ (public-key
+ (rsa
+ (n N-MPI)
+ (e E-MPI)))
+
+N-MPI
+ RSA public modulus n.
+E-MPI
+ RSA public exponent e.
+D-MPI
+ RSA secret exponent d = e^{-1} \bmod (p-1)(q-1).
+P-MPI
+ RSA secret prime p.
+Q-MPI
+ RSA secret prime q with p < q.
+U-MPI
+ Multiplicative inverse u = p^{-1} \bmod q.
+
+ For signing and decryption the parameters (p, q, u) are optional but
+greatly improve the performance. Either all of these optional
+parameters must be given or none of them. They are mandatory for
+gcry_pk_testkey.
+
+ Note that OpenSSL uses slighly different parameters: q < p and u =
+q^{-1} \bmod p. To use these parameters you will need to swap the
+values and recompute u. Here is example code to do this:
+
+ if (gcry_mpi_cmp (p, q) > 0)
+ {
+ gcry_mpi_swap (p, q);
+ gcry_mpi_invm (u, p, q);
+ }
+
+\1f
+File: gcrypt.info, Node: DSA key parameters, Next: ECC key parameters, Prev: RSA key parameters, Up: Used S-expressions
+
+6.2.2 DSA key parameters
+------------------------
+
+A DSA private key is described by this S-expression:
+
+ (private-key
+ (dsa
+ (p P-MPI)
+ (q Q-MPI)
+ (g G-MPI)
+ (y Y-MPI)
+ (x X-MPI)))
+
+P-MPI
+ DSA prime p.
+Q-MPI
+ DSA group order q (which is a prime divisor of p-1).
+G-MPI
+ DSA group generator g.
+Y-MPI
+ DSA public key value y = g^x \bmod p.
+X-MPI
+ DSA secret exponent x.
+
+ The public key is similar with "private-key" replaced by "public-key"
+and no X-MPI.
+
+\1f
+File: gcrypt.info, Node: ECC key parameters, Prev: DSA key parameters, Up: Used S-expressions
+
+6.2.3 ECC key parameters
+------------------------
+
+An ECC private key is described by this S-expression:
+
+ (private-key
+ (ecc
+ (p P-MPI)
+ (a A-MPI)
+ (b B-MPI)
+ (g G-POINT)
+ (n N-MPI)
+ (q Q-POINT)
+ (d D-MPI)))
+
+P-MPI
+ Prime specifying the field GF(p).
+A-MPI
+B-MPI
+ The two coefficients of the Weierstrass equation y^2 = x^3 + ax + b
+G-POINT
+ Base point g.
+N-MPI
+ Order of g
+Q-POINT
+ The point representing the public key Q = dG.
+D-MPI
+ The private key d
+
+ All point values are encoded in standard format; Libgcrypt does in
+general only support uncompressed points, thus the first byte needs to
+be '0x04'. However "EdDSA" describes its own compression scheme which
+is used by default; the non-standard first byte '0x40' may optionally be
+used to explicit flag the use of the algorithm’s native compression
+method.
+
+ The public key is similar with "private-key" replaced by "public-key"
+and no D-MPI.
+
+ If the domain parameters are well-known, the name of this curve may
+be used. For example
+
+ (private-key
+ (ecc
+ (curve "NIST P-192")
+ (q Q-POINT)
+ (d D-MPI)))
+
+ Note that Q-POINT is optional for a private key. The 'curve'
+parameter may be given in any case and is used to replace missing
+parameters.
+
+Currently implemented curves are:
+'NIST P-192'
+'1.2.840.10045.3.1.1'
+'prime192v1'
+'secp192r1'
+ The NIST 192 bit curve, its OID, X9.62 and SECP aliases.
+
+'NIST P-224'
+'secp224r1'
+ The NIST 224 bit curve and its SECP alias.
+
+'NIST P-256'
+'1.2.840.10045.3.1.7'
+'prime256v1'
+'secp256r1'
+ The NIST 256 bit curve, its OID, X9.62 and SECP aliases.
+
+'NIST P-384'
+'secp384r1'
+ The NIST 384 bit curve and its SECP alias.
+
+'NIST P-521'
+'secp521r1'
+ The NIST 521 bit curve and its SECP alias.
+
+ As usual the OIDs may optionally be prefixed with the string 'OID.'
+or 'oid.'.
+
+\1f
+File: gcrypt.info, Node: Cryptographic Functions, Next: General public-key related Functions, Prev: Used S-expressions, Up: Public Key cryptography
+
+6.3 Cryptographic Functions
+===========================
+
+Some functions operating on S-expressions support 'flags' to influence
+the operation. These flags have to be listed in a sub-S-expression
+named 'flags'. Flag names are case-sensitive. The following flags are
+known:
+
+'comp'
+'nocomp'
+ If supported by the algorithm and curve the 'comp' flag requests
+ that points are returned in compact (compressed) representation.
+ The 'nocomp' flag requests that points are returned with full
+ coordinates. The default depends on the the algorithm and curve.
+ The compact representation requires a small overhead before a point
+ can be used but halves the size of a to be conveyed public key. If
+ 'comp' is used with the "EdDSA" algorithm the key generation prefix
+ the public key with a '0x40' byte.
+
+'pkcs1'
+ Use PKCS#1 block type 2 padding for encryption, block type 1
+ padding for signing.
+
+'oaep'
+ Use RSA-OAEP padding for encryption.
+
+'pss'
+ Use RSA-PSS padding for signing.
+
+'eddsa'
+ Use the EdDSA scheme signing instead of the default ECDSA
+ algorithm. Note that the EdDSA uses a special form of the public
+ key.
+
+'rfc6979'
+ For DSA and ECDSA use a deterministic scheme for the k parameter.
+
+'no-blinding'
+ Do not use a technique called 'blinding', which is used by default
+ in order to prevent leaking of secret information. Blinding is
+ only implemented by RSA, but it might be implemented by other
+ algorithms in the future as well, when necessary.
+
+'param'
+ For ECC key generation also return the domain parameters. For ECC
+ signing and verification override default parameters by provided
+ domain parameters of the public or private key.
+
+'transient-key'
+ This flag is only meaningful for RSA, DSA, and ECC key generation.
+ If given the key is created using a faster and a somewhat less
+ secure random number generator. This flag may be used for keys
+ which are only used for a short time or per-message and do not
+ require full cryptographic strength.
+
+'no-keytest'
+ This flag skips internal failsafe tests to assert that a generated
+ key is properly working. It currently has an effect only for
+ standard ECC key generation. It is mostly useful along with
+ transient-key to achieve fastest ECC key generation.
+
+'use-x931'
+ Force the use of the ANSI X9.31 key generation algorithm instead of
+ the default algorithm. This flag is only meaningful for RSA key
+ generation and usually not required. Note that this algorithm is
+ implicitly used if either 'derive-parms' is given or Libgcrypt is
+ in FIPS mode.
+
+'use-fips186'
+ Force the use of the FIPS 186 key generation algorithm instead of
+ the default algorithm. This flag is only meaningful for DSA and
+ usually not required. Note that this algorithm is implicitly used
+ if either 'derive-parms' is given or Libgcrypt is in FIPS mode. As
+ of now FIPS 186-2 is implemented; after the approval of FIPS 186-3
+ the code will be changed to implement 186-3.
+
+'use-fips186-2'
+ Force the use of the FIPS 186-2 key generation algorithm instead of
+ the default algorithm. This algorithm is slightly different from
+ FIPS 186-3 and allows only 1024 bit keys. This flag is only
+ meaningful for DSA and only required for FIPS testing backward
+ compatibility.
+
+Now that we know the key basics, we can carry on and explain how to
+encrypt and decrypt data. In almost all cases the data is a random
+session key which is in turn used for the actual encryption of the real
+data. There are 2 functions to do this:
+
+ -- Function: gcry_error_t gcry_pk_encrypt (gcry_sexp_t *R_CIPH,
+ gcry_sexp_t DATA, gcry_sexp_t PKEY)
+
+ Obviously a public key must be provided for encryption. It is
+ expected as an appropriate S-expression (see above) in PKEY. The
+ data to be encrypted can either be in the simple old format, which
+ is a very simple S-expression consisting only of one MPI, or it may
+ be a more complex S-expression which also allows to specify flags
+ for operation, like e.g. padding rules.
+
+ If you don't want to let Libgcrypt handle the padding, you must
+ pass an appropriate MPI using this expression for DATA:
+
+ (data
+ (flags raw)
+ (value MPI))
+
+ This has the same semantics as the old style MPI only way. MPI is
+ the actual data, already padded appropriate for your protocol.
+ Most RSA based systems however use PKCS#1 padding and so you can
+ use this S-expression for DATA:
+
+ (data
+ (flags pkcs1)
+ (value BLOCK))
+
+ Here, the "flags" list has the "pkcs1" flag which let the function
+ know that it should provide PKCS#1 block type 2 padding. The
+ actual data to be encrypted is passed as a string of octets in
+ BLOCK. The function checks that this data actually can be used
+ with the given key, does the padding and encrypts it.
+
+ If the function could successfully perform the encryption, the
+ return value will be 0 and a new S-expression with the encrypted
+ result is allocated and assigned to the variable at the address of
+ R_CIPH. The caller is responsible to release this value using
+ 'gcry_sexp_release'. In case of an error, an error code is
+ returned and R_CIPH will be set to 'NULL'.
+
+ The returned S-expression has this format when used with RSA:
+
+ (enc-val
+ (rsa
+ (a A-MPI)))
+
+ Where A-MPI is an MPI with the result of the RSA operation. When
+ using the Elgamal algorithm, the return value will have this
+ format:
+
+ (enc-val
+ (elg
+ (a A-MPI)
+ (b B-MPI)))
+
+ Where A-MPI and B-MPI are MPIs with the result of the Elgamal
+ encryption operation.
+
+ -- Function: gcry_error_t gcry_pk_decrypt (gcry_sexp_t *R_PLAIN,
+ gcry_sexp_t DATA, gcry_sexp_t SKEY)
+
+ Obviously a private key must be provided for decryption. It is
+ expected as an appropriate S-expression (see above) in SKEY. The
+ data to be decrypted must match the format of the result as
+ returned by 'gcry_pk_encrypt', but should be enlarged with a
+ 'flags' element:
+
+ (enc-val
+ (flags)
+ (elg
+ (a A-MPI)
+ (b B-MPI)))
+
+ This function does not remove padding from the data by default. To
+ let Libgcrypt remove padding, give a hint in 'flags' telling which
+ padding method was used when encrypting:
+
+ (flags PADDING-METHOD)
+
+ Currently PADDING-METHOD is either 'pkcs1' for PKCS#1 block type 2
+ padding, or 'oaep' for RSA-OAEP padding.
+
+ The function returns 0 on success or an error code. The variable
+ at the address of R_PLAIN will be set to NULL on error or receive
+ the decrypted value on success. The format of R_PLAIN is a simple
+ S-expression part (i.e. not a valid one) with just one MPI if
+ there was no 'flags' element in DATA; if at least an empty 'flags'
+ is passed in DATA, the format is:
+
+ (value PLAINTEXT)
+
+ Another operation commonly performed using public key cryptography is
+signing data. In some sense this is even more important than encryption
+because digital signatures are an important instrument for key
+management. Libgcrypt supports digital signatures using 2 functions,
+similar to the encryption functions:
+
+ -- Function: gcry_error_t gcry_pk_sign (gcry_sexp_t *R_SIG,
+ gcry_sexp_t DATA, gcry_sexp_t SKEY)
+
+ This function creates a digital signature for DATA using the
+ private key SKEY and place it into the variable at the address of
+ R_SIG. DATA may either be the simple old style S-expression with
+ just one MPI or a modern and more versatile S-expression which
+ allows to let Libgcrypt handle padding:
+
+ (data
+ (flags pkcs1)
+ (hash HASH-ALGO BLOCK))
+
+ This example requests to sign the data in BLOCK after applying
+ PKCS#1 block type 1 style padding. HASH-ALGO is a string with the
+ hash algorithm to be encoded into the signature, this may be any
+ hash algorithm name as supported by Libgcrypt. Most likely, this
+ will be "sha256" or "sha1". It is obvious that the length of BLOCK
+ must match the size of that message digests; the function checks
+ that this and other constraints are valid.
+
+ If PKCS#1 padding is not required (because the caller does already
+ provide a padded value), either the old format or better the
+ following format should be used:
+
+ (data
+ (flags raw)
+ (value MPI))
+
+ Here, the data to be signed is directly given as an MPI.
+
+ For DSA the input data is expected in this format:
+
+ (data
+ (flags raw)
+ (value MPI))
+
+ Here, the data to be signed is directly given as an MPI. It is
+ expect that this MPI is the the hash value. For the standard DSA
+ using a MPI is not a problem in regard to leading zeroes because
+ the hash value is directly used as an MPI. For better standard
+ conformance it would be better to explicit use a memory string
+ (like with pkcs1) but that is currently not supported. However,
+ for deterministic DSA as specified in RFC6979 this can't be used.
+ Instead the following input is expected.
+
+ (data
+ (flags rfc6979)
+ (hash HASH-ALGO BLOCK))
+
+ Note that the provided hash-algo is used for the internal HMAC; it
+ should match the hash-algo used to create BLOCK.
+
+ The signature is returned as a newly allocated S-expression in
+ R_SIG using this format for RSA:
+
+ (sig-val
+ (rsa
+ (s S-MPI)))
+
+ Where S-MPI is the result of the RSA sign operation. For DSA the
+ S-expression returned is:
+
+ (sig-val
+ (dsa
+ (r R-MPI)
+ (s S-MPI)))
+
+ Where R-MPI and S-MPI are the result of the DSA sign operation.
+
+ For Elgamal signing (which is slow, yields large numbers, hard to
+ use correctly and probably is not as secure as the other
+ algorithms), the same format is used with "elg" replacing "dsa";
+ for ECDSA signing, the same format is used with "ecdsa" replacing
+ "dsa".
+
+ For the EdDSA algorithm (cf. Ed25515) the required input
+ parameters are:
+
+ (data
+ (flags eddsa)
+ (hash-algo sha512)
+ (value MESSAGE))
+
+ Note that the MESSAGE may be of any length; hashing is part of the
+ algorithm. Using a large data block for MESSAGE is not suggested;
+ in that case the used protocol should better require that a hash of
+ the message is used as input to the EdDSA algorithm.
+
+The operation most commonly used is definitely the verification of a
+signature. Libgcrypt provides this function:
+
+ -- Function: gcry_error_t gcry_pk_verify (gcry_sexp_t SIG,
+ gcry_sexp_t DATA, gcry_sexp_t PKEY)
+
+ This is used to check whether the signature SIG matches the DATA.
+ The public key PKEY must be provided to perform this verification.
+ This function is similar in its parameters to 'gcry_pk_sign' with
+ the exceptions that the public key is used instead of the private
+ key and that no signature is created but a signature, in a format
+ as created by 'gcry_pk_sign', is passed to the function in SIG.
+
+ The result is 0 for success (i.e. the data matches the signature),
+ or an error code where the most relevant code is
+ 'GCRY_ERR_BAD_SIGNATURE' to indicate that the signature does not
+ match the provided data.
+
+\1f
+File: gcrypt.info, Node: General public-key related Functions, Prev: Cryptographic Functions, Up: Public Key cryptography
+
+6.4 General public-key related Functions
+========================================
+
+A couple of utility functions are available to retrieve the length of
+the key, map algorithm identifiers and perform sanity checks:
+
+ -- Function: const char * gcry_pk_algo_name (int ALGO)
+
+ Map the public key algorithm id ALGO to a string representation of
+ the algorithm name. For unknown algorithms this functions returns
+ the string '"?"'. This function should not be used to test for the
+ availability of an algorithm.
+
+ -- Function: int gcry_pk_map_name (const char *NAME)
+
+ Map the algorithm NAME to a public key algorithm Id. Returns 0 if
+ the algorithm name is not known.
+
+ -- Function: int gcry_pk_test_algo (int ALGO)
+
+ Return 0 if the public key algorithm ALGO is available for use.
+ Note that this is implemented as a macro.
+
+ -- Function: unsigned int gcry_pk_get_nbits (gcry_sexp_t KEY)
+
+ Return what is commonly referred as the key length for the given
+ public or private in KEY.
+
+ -- Function: unsigned char * gcry_pk_get_keygrip (gcry_sexp_t KEY,
+ unsigned char *ARRAY)
+
+ Return the so called "keygrip" which is the SHA-1 hash of the
+ public key parameters expressed in a way depended on the algorithm.
+ ARRAY must either provide space for 20 bytes or be 'NULL'. In the
+ latter case a newly allocated array of that size is returned. On
+ success a pointer to the newly allocated space or to ARRAY is
+ returned. 'NULL' is returned to indicate an error which is most
+ likely an unknown algorithm or one where a "keygrip" has not yet
+ been defined. The function accepts public or secret keys in KEY.
+
+ -- Function: gcry_error_t gcry_pk_testkey (gcry_sexp_t KEY)
+
+ Return zero if the private key KEY is 'sane', an error code
+ otherwise. Note that it is not possible to check the 'saneness' of
+ a public key.
+
+ -- Function: gcry_error_t gcry_pk_algo_info (int ALGO, int WHAT,
+ void *BUFFER, size_t *NBYTES)
+
+ Depending on the value of WHAT return various information about the
+ public key algorithm with the id ALGO. Note that the function
+ returns '-1' on error and the actual error code must be retrieved
+ using the function 'gcry_errno'. The currently defined values for
+ WHAT are:
+
+ 'GCRYCTL_TEST_ALGO:'
+ Return 0 if the specified algorithm is available for use.
+ BUFFER must be 'NULL', NBYTES may be passed as 'NULL' or point
+ to a variable with the required usage of the algorithm. This
+ may be 0 for "don't care" or the bit-wise OR of these flags:
+
+ 'GCRY_PK_USAGE_SIGN'
+ Algorithm is usable for signing.
+ 'GCRY_PK_USAGE_ENCR'
+ Algorithm is usable for encryption.
+
+ Unless you need to test for the allowed usage, it is in
+ general better to use the macro gcry_pk_test_algo instead.
+
+ 'GCRYCTL_GET_ALGO_USAGE:'
+ Return the usage flags for the given algorithm. An invalid
+ algorithm return 0. Disabled algorithms are ignored here
+ because we want to know whether the algorithm is at all
+ capable of a certain usage.
+
+ 'GCRYCTL_GET_ALGO_NPKEY'
+ Return the number of elements the public key for algorithm
+ ALGO consist of. Return 0 for an unknown algorithm.
+
+ 'GCRYCTL_GET_ALGO_NSKEY'
+ Return the number of elements the private key for algorithm
+ ALGO consist of. Note that this value is always larger than
+ that of the public key. Return 0 for an unknown algorithm.
+
+ 'GCRYCTL_GET_ALGO_NSIGN'
+ Return the number of elements a signature created with the
+ algorithm ALGO consists of. Return 0 for an unknown algorithm
+ or for an algorithm not capable of creating signatures.
+
+ 'GCRYCTL_GET_ALGO_NENC'
+ Return the number of elements a encrypted message created with
+ the algorithm ALGO consists of. Return 0 for an unknown
+ algorithm or for an algorithm not capable of encryption.
+
+ Please note that parameters not required should be passed as
+ 'NULL'.
+
+ -- Function: gcry_error_t gcry_pk_ctl (int CMD, void *BUFFER,
+ size_t BUFLEN)
+
+ This is a general purpose function to perform certain control
+ operations. CMD controls what is to be done. The return value is
+ 0 for success or an error code. Currently supported values for CMD
+ are:
+
+ 'GCRYCTL_DISABLE_ALGO'
+ Disable the algorithm given as an algorithm id in BUFFER.
+ BUFFER must point to an 'int' variable with the algorithm id
+ and BUFLEN must have the value 'sizeof (int)'. This function
+ is not thread safe and should thus be used before any other
+ threads are started.
+
+Libgcrypt also provides a function to generate public key pairs:
+
+ -- Function: gcry_error_t gcry_pk_genkey (gcry_sexp_t *R_KEY,
+ gcry_sexp_t PARMS)
+
+ This function create a new public key pair using information given
+ in the S-expression PARMS and stores the private and the public key
+ in one new S-expression at the address given by R_KEY. In case of
+ an error, R_KEY is set to 'NULL'. The return code is 0 for success
+ or an error code otherwise.
+
+ Here is an example for PARMS to create an 2048 bit RSA key:
+
+ (genkey
+ (rsa
+ (nbits 4:2048)))
+
+ To create an Elgamal key, substitute "elg" for "rsa" and to create
+ a DSA key use "dsa". Valid ranges for the key length depend on the
+ algorithms; all commonly used key lengths are supported. Currently
+ supported parameters are:
+
+ 'nbits'
+ This is always required to specify the length of the key. The
+ argument is a string with a number in C-notation. The value
+ should be a multiple of 8. Note that the S-expression syntax
+ requires that a number is prefixed with its string length;
+ thus the '4:' in the above example.
+
+ 'curve NAME'
+ For ECC a named curve may be used instead of giving the number
+ of requested bits. This allows to request a specific curve to
+ override a default selection Libgcrypt would have taken if
+ 'nbits' has been given. The available names are listed with
+ the description of the ECC public key parameters.
+
+ 'rsa-use-e VALUE'
+ This is only used with RSA to give a hint for the public
+ exponent. The VALUE will be used as a base to test for a
+ usable exponent. Some values are special:
+
+ '0'
+ Use a secure and fast value. This is currently the
+ number 41.
+ '1'
+ Use a value as required by some crypto policies. This is
+ currently the number 65537.
+ '2'
+ Reserved
+ '> 2'
+ Use the given value.
+
+ If this parameter is not used, Libgcrypt uses for historic
+ reasons 65537. Note that the value must fit into a 32 bit
+ unsigned variable and that the usual C prefixes are considered
+ (e.g. 017 gives 15).
+
+ 'qbits N'
+ This is only meanigful for DSA keys. If it is given the DSA
+ key is generated with a Q parameyer of size N bits. If it is
+ not given or zero Q is deduced from NBITS in this way:
+ '512 <= N <= 1024'
+ Q = 160
+ 'N = 2048'
+ Q = 224
+ 'N = 3072'
+ Q = 256
+ 'N = 7680'
+ Q = 384
+ 'N = 15360'
+ Q = 512
+ Note that in this case only the values for N, as given in the
+ table, are allowed. When specifying Q all values of N in the
+ range 512 to 15680 are valid as long as they are multiples of
+ 8.
+
+ 'domain LIST'
+ This is only meaningful for DLP algorithms. If specified keys
+ are generated with domain parameters taken from this list.
+ The exact format of this parameter depends on the actual
+ algorithm. It is currently only implemented for DSA using
+ this format:
+
+ (genkey
+ (dsa
+ (domain
+ (p P-MPI)
+ (q Q-MPI)
+ (g Q-MPI))))
+
+ 'nbits' and 'qbits' may not be specified because they are
+ derived from the domain parameters.
+
+ 'derive-parms LIST'
+ This is currently only implemented for RSA and DSA keys. It
+ is not allowed to use this together with a 'domain'
+ specification. If given, it is used to derive the keys using
+ the given parameters.
+
+ If given for an RSA key the X9.31 key generation algorithm is
+ used even if libgcrypt is not in FIPS mode. If given for a
+ DSA key, the FIPS 186 algorithm is used even if libgcrypt is
+ not in FIPS mode.
+
+ (genkey
+ (rsa
+ (nbits 4:1024)
+ (rsa-use-e 1:3)
+ (derive-parms
+ (Xp1 #1A1916DDB29B4EB7EB6732E128#)
+ (Xp2 #192E8AAC41C576C822D93EA433#)
+ (Xp #D8CD81F035EC57EFE822955149D3BFF70C53520D
+ 769D6D76646C7A792E16EBD89FE6FC5B605A6493
+ 39DFC925A86A4C6D150B71B9EEA02D68885F5009
+ B98BD984#)
+ (Xq1 #1A5CF72EE770DE50CB09ACCEA9#)
+ (Xq2 #134E4CAA16D2350A21D775C404#)
+ (Xq #CC1092495D867E64065DEE3E7955F2EBC7D47A2D
+ 7C9953388F97DDDC3E1CA19C35CA659EDC2FC325
+ 6D29C2627479C086A699A49C4C9CEE7EF7BD1B34
+ 321DE34A#))))
+
+ (genkey
+ (dsa
+ (nbits 4:1024)
+ (derive-parms
+ (seed SEED-MPI))))
+
+ 'flags FLAGLIST'
+ This is preferred way to define flags. FLAGLIST may contain
+ any number of flags. See above for a specification of these
+ flags.
+
+ Here is an example on how to create a key using curve Ed25519
+ with the ECDSA signature algorithm. Note that the use of
+ ECDSA with that curve is in general not recommended.
+ (genkey
+ (ecc
+ (flags transient-key)))
+
+ 'transient-key'
+ 'use-x931'
+ 'use-fips186'
+ 'use-fips186-2'
+ These are deprecated ways to set a flag with that name; see
+ above for a description of each flag.
+
+ The key pair is returned in a format depending on the algorithm.
+ Both private and public keys are returned in one container and may
+ be accompanied by some miscellaneous information.
+
+ Here are two examples; the first for Elgamal and the second for
+ elliptic curve key generation:
+
+ (key-data
+ (public-key
+ (elg
+ (p P-MPI)
+ (g G-MPI)
+ (y Y-MPI)))
+ (private-key
+ (elg
+ (p P-MPI)
+ (g G-MPI)
+ (y Y-MPI)
+ (x X-MPI)))
+ (misc-key-info
+ (pm1-factors N1 N2 ... NN))
+
+ (key-data
+ (public-key
+ (ecc
+ (curve Ed25519)
+ (flags eddsa)
+ (q Q-VALUE)))
+ (private-key
+ (ecc
+ (curve Ed25519)
+ (flags eddsa)
+ (q Q-VALUE)
+ (d D-VALUE))))
+
+ As you can see, some of the information is duplicated, but this
+ provides an easy way to extract either the public or the private
+ key. Note that the order of the elements is not defined, e.g. the
+ private key may be stored before the public key. N1 N2 ... NN is a
+ list of prime numbers used to composite P-MPI; this is in general
+ not a very useful information and only available if the key
+ generation algorithm provides them.
+
+Future versions of Libgcrypt will have extended versions of the public
+key interfaced which will take an additional context to allow for
+pre-computations, special operations, and other optimization. As a
+first step a new function is introduced to help using the ECC algorithms
+in new ways:
+
+ -- Function: gcry_error_t gcry_pubkey_get_sexp (gcry_sexp_t *R_SEXP,
+ int MODE, gcry_ctx_t CTX)
+
+ Return an S-expression representing the context CTX. Depending on
+ the state of that context, the S-expression may either be a public
+ key, a private key or any other object used with public key
+ operations. On success 0 is returned and a new S-expression is
+ stored at R_SEXP; on error an error code is returned and NULL is
+ stored at R_SEXP. MODE must be one of:
+
+ '0'
+ Decide what to return depending on the context. For example
+ if the private key parameter is available a private key is
+ returned, if not a public key is returned.
+
+ 'GCRY_PK_GET_PUBKEY'
+ Return the public key even if the context has the private key
+ parameter.
+
+ 'GCRY_PK_GET_SECKEY'
+ Return the private key or the error 'GPG_ERR_NO_SECKEY' if it
+ is not possible.
+
+ As of now this function supports only certain ECC operations
+ because a context object is right now only defined for ECC. Over
+ time this function will be extended to cover more algorithms.
+
+\1f
+File: gcrypt.info, Node: Hashing, Next: Message Authentication Codes, Prev: Public Key cryptography, Up: Top
+
+7 Hashing
+*********
+
+Libgcrypt provides an easy and consistent to use interface for hashing.
+Hashing is buffered and several hash algorithms can be updated at once.
+It is possible to compute a HMAC using the same routines. The
+programming model follows an open/process/close paradigm and is in that
+similar to other building blocks provided by Libgcrypt.
+
+ For convenience reasons, a few cyclic redundancy check value
+operations are also supported.
+
+* Menu:
+
+* Available hash algorithms:: List of hash algorithms supported by the library.
+* Working with hash algorithms:: List of functions related to hashing.
+
+\1f
+File: gcrypt.info, Node: Available hash algorithms, Next: Working with hash algorithms, Up: Hashing
+
+7.1 Available hash algorithms
+=============================
+
+'GCRY_MD_NONE'
+ This is not a real algorithm but used by some functions as an error
+ return value. This constant is guaranteed to have the value '0'.
+
+'GCRY_MD_SHA1'
+ This is the SHA-1 algorithm which yields a message digest of 20
+ bytes. Note that SHA-1 begins to show some weaknesses and it is
+ suggested to fade out its use if strong cryptographic properties
+ are required.
+
+'GCRY_MD_RMD160'
+ This is the 160 bit version of the RIPE message digest
+ (RIPE-MD-160). Like SHA-1 it also yields a digest of 20 bytes.
+ This algorithm share a lot of design properties with SHA-1 and thus
+ it is advisable not to use it for new protocols.
+
+'GCRY_MD_MD5'
+ This is the well known MD5 algorithm, which yields a message digest
+ of 16 bytes. Note that the MD5 algorithm has severe weaknesses,
+ for example it is easy to compute two messages yielding the same
+ hash (collision attack). The use of this algorithm is only
+ justified for non-cryptographic application.
+
+'GCRY_MD_MD4'
+ This is the MD4 algorithm, which yields a message digest of 16
+ bytes. This algorithm has severe weaknesses and should not be
+ used.
+
+'GCRY_MD_MD2'
+ This is an reserved identifier for MD-2; there is no implementation
+ yet. This algorithm has severe weaknesses and should not be used.
+
+'GCRY_MD_TIGER'
+ This is the TIGER/192 algorithm which yields a message digest of 24
+ bytes. Actually this is a variant of TIGER with a different output
+ print order as used by GnuPG up to version 1.3.2.
+
+'GCRY_MD_TIGER1'
+ This is the TIGER variant as used by the NESSIE project. It uses
+ the most commonly used output print order.
+
+'GCRY_MD_TIGER2'
+ This is another variant of TIGER with a different padding scheme.
+
+'GCRY_MD_HAVAL'
+ This is an reserved value for the HAVAL algorithm with 5 passes and
+ 160 bit. It yields a message digest of 20 bytes. Note that there
+ is no implementation yet available.
+
+'GCRY_MD_SHA224'
+ This is the SHA-224 algorithm which yields a message digest of 28
+ bytes. See Change Notice 1 for FIPS 180-2 for the specification.
+
+'GCRY_MD_SHA256'
+ This is the SHA-256 algorithm which yields a message digest of 32
+ bytes. See FIPS 180-2 for the specification.
+
+'GCRY_MD_SHA384'
+ This is the SHA-384 algorithm which yields a message digest of 48
+ bytes. See FIPS 180-2 for the specification.
+
+'GCRY_MD_SHA512'
+ This is the SHA-384 algorithm which yields a message digest of 64
+ bytes. See FIPS 180-2 for the specification.
+
+'GCRY_MD_SHA3_224'
+ This is the SHA3-224 algorithm which yields a message digest of 28
+ bytes. See FIPS 202 for the specification.
+
+'GCRY_MD_SHA3_256'
+ This is the SHA3-256 algorithm which yields a message digest of 32
+ bytes. See FIPS 202 for the specification.
+
+'GCRY_MD_SHA3_384'
+ This is the SHA3-384 algorithm which yields a message digest of 48
+ bytes. See FIPS 202 for the specification.
+
+'GCRY_MD_SHA3_512'
+ This is the SHA3-384 algorithm which yields a message digest of 64
+ bytes. See FIPS 202 for the specification.
+
+'GCRY_MD_SHAKE128'
+ This is the SHAKE128 extendable-output function (XOF) algorithm
+ with 128 bit security strength. See FIPS 202 for the
+ specification.
+
+'GCRY_MD_SHAKE256'
+ This is the SHAKE256 extendable-output function (XOF) algorithm
+ with 256 bit security strength. See FIPS 202 for the
+ specification.
+
+'GCRY_MD_CRC32'
+ This is the ISO 3309 and ITU-T V.42 cyclic redundancy check. It
+ yields an output of 4 bytes. Note that this is not a hash
+ algorithm in the cryptographic sense.
+
+'GCRY_MD_CRC32_RFC1510'
+ This is the above cyclic redundancy check function, as modified by
+ RFC 1510. It yields an output of 4 bytes. Note that this is not a
+ hash algorithm in the cryptographic sense.
+
+'GCRY_MD_CRC24_RFC2440'
+ This is the OpenPGP cyclic redundancy check function. It yields an
+ output of 3 bytes. Note that this is not a hash algorithm in the
+ cryptographic sense.
+
+'GCRY_MD_WHIRLPOOL'
+ This is the Whirlpool algorithm which yields a message digest of 64
+ bytes.
+
+'GCRY_MD_GOSTR3411_94'
+ This is the hash algorithm described in GOST R 34.11-94 which
+ yields a message digest of 32 bytes.
+
+'GCRY_MD_STRIBOG256'
+ This is the 256-bit version of hash algorithm described in GOST R
+ 34.11-2012 which yields a message digest of 32 bytes.
+
+'GCRY_MD_STRIBOG512'
+ This is the 512-bit version of hash algorithm described in GOST R
+ 34.11-2012 which yields a message digest of 64 bytes.
+
+'GCRY_MD_BLAKE2B_512'
+ This is the BLAKE2b-512 algorithm which yields a message digest of
+ 64 bytes. See RFC 7693 for the specification.
+
+'GCRY_MD_BLAKE2B_384'
+ This is the BLAKE2b-384 algorithm which yields a message digest of
+ 48 bytes. See RFC 7693 for the specification.
+
+'GCRY_MD_BLAKE2B_256'
+ This is the BLAKE2b-256 algorithm which yields a message digest of
+ 32 bytes. See RFC 7693 for the specification.
+
+'GCRY_MD_BLAKE2B_160'
+ This is the BLAKE2b-160 algorithm which yields a message digest of
+ 20 bytes. See RFC 7693 for the specification.
+
+'GCRY_MD_BLAKE2S_256'
+ This is the BLAKE2s-256 algorithm which yields a message digest of
+ 32 bytes. See RFC 7693 for the specification.
+
+'GCRY_MD_BLAKE2S_224'
+ This is the BLAKE2s-224 algorithm which yields a message digest of
+ 28 bytes. See RFC 7693 for the specification.
+
+'GCRY_MD_BLAKE2S_160'
+ This is the BLAKE2s-160 algorithm which yields a message digest of
+ 20 bytes. See RFC 7693 for the specification.
+
+'GCRY_MD_BLAKE2S_128'
+ This is the BLAKE2s-128 algorithm which yields a message digest of
+ 16 bytes. See RFC 7693 for the specification.
+
+\1f
+File: gcrypt.info, Node: Working with hash algorithms, Prev: Available hash algorithms, Up: Hashing
+
+7.2 Working with hash algorithms
+================================
+
+To use most of these function it is necessary to create a context; this
+is done using:
+
+ -- Function: gcry_error_t gcry_md_open (gcry_md_hd_t *HD, int ALGO,
+ unsigned int FLAGS)
+
+ Create a message digest object for algorithm ALGO. FLAGS may be
+ given as an bitwise OR of constants described below. ALGO may be
+ given as '0' if the algorithms to use are later set using
+ 'gcry_md_enable'. HD is guaranteed to either receive a valid
+ handle or NULL.
+
+ For a list of supported algorithms, see *note Available hash
+ algorithms::.
+
+ The flags allowed for MODE are:
+
+ 'GCRY_MD_FLAG_SECURE'
+ Allocate all buffers and the resulting digest in "secure
+ memory". Use this is the hashed data is highly confidential.
+
+ 'GCRY_MD_FLAG_HMAC'
+ Turn the algorithm into a HMAC message authentication
+ algorithm. This only works if just one algorithm is enabled
+ for the handle and that algorithm is not an extendable-output
+ function. Note that the function 'gcry_md_setkey' must be
+ used to set the MAC key. The size of the MAC is equal to the
+ message digest of the underlying hash algorithm. If you want
+ CBC message authentication codes based on a cipher, see *note
+ Working with cipher handles::.
+
+ 'GCRY_MD_FLAG_BUGEMU1'
+ Versions of Libgcrypt before 1.6.0 had a bug in the Whirlpool
+ code which led to a wrong result for certain input sizes and
+ write patterns. Using this flag emulates that bug. This may
+ for example be useful for applications which use Whirlpool as
+ part of their key generation. It is strongly suggested to use
+ this flag only if really needed and if possible to the data
+ should be re-processed using the regular Whirlpool algorithm.
+
+ Note that this flag works for the entire hash context. If
+ needed arises it may be used to enable bug emulation for other
+ hash algorithms. Thus you should not use this flag for a
+ multi-algorithm hash context.
+
+ You may use the function 'gcry_md_is_enabled' to later check
+ whether an algorithm has been enabled.
+
+ If you want to calculate several hash algorithms at the same time,
+you have to use the following function right after the 'gcry_md_open':
+
+ -- Function: gcry_error_t gcry_md_enable (gcry_md_hd_t H, int ALGO)
+
+ Add the message digest algorithm ALGO to the digest object
+ described by handle H. Duplicated enabling of algorithms is
+ detected and ignored.
+
+ If the flag 'GCRY_MD_FLAG_HMAC' was used, the key for the MAC must be
+set using the function:
+
+ -- Function: gcry_error_t gcry_md_setkey (gcry_md_hd_t H, const void
+ *KEY, size_t KEYLEN)
+
+ For use with the HMAC feature or BLAKE2 keyed hash, set the MAC key
+ to the value of KEY of length KEYLEN bytes. For HMAC, there is no
+ restriction on the length of the key. For keyed BLAKE2b hash,
+ length of the key must be 64 bytes or less. For keyed BLAKE2s
+ hash, length of the key must be 32 bytes or less.
+
+ After you are done with the hash calculation, you should release the
+resources by using:
+
+ -- Function: void gcry_md_close (gcry_md_hd_t H)
+
+ Release all resources of hash context H. H should not be used
+ after a call to this function. A 'NULL' passed as H is ignored.
+ The function also zeroises all sensitive information associated
+ with this handle.
+
+ Often you have to do several hash operations using the same
+algorithm. To avoid the overhead of creating and releasing context, a
+reset function is provided:
+
+ -- Function: void gcry_md_reset (gcry_md_hd_t H)
+
+ Reset the current context to its initial state. This is
+ effectively identical to a close followed by an open and enabling
+ all currently active algorithms.
+
+ Often it is necessary to start hashing some data and then continue to
+hash different data. To avoid hashing the same data several times
+(which might not even be possible if the data is received from a pipe),
+a snapshot of the current hash context can be taken and turned into a
+new context:
+
+ -- Function: gcry_error_t gcry_md_copy (gcry_md_hd_t *HANDLE_DST,
+ gcry_md_hd_t HANDLE_SRC)
+
+ Create a new digest object as an exact copy of the object described
+ by handle HANDLE_SRC and store it in HANDLE_DST. The context is
+ not reset and you can continue to hash data using this context and
+ independently using the original context.
+
+ Now that we have prepared everything to calculate hashes, it is time
+to see how it is actually done. There are two ways for this, one to
+update the hash with a block of memory and one macro to update the hash
+by just one character. Both methods can be used on the same hash
+context.
+
+ -- Function: void gcry_md_write (gcry_md_hd_t H, const void *BUFFER,
+ size_t LENGTH)
+
+ Pass LENGTH bytes of the data in BUFFER to the digest object with
+ handle H to update the digest values. This function should be used
+ for large blocks of data. If this function is used after the
+ context has been finalized, it will keep on pushing the data
+ through the algorithm specific transform function and change the
+ context; however the results are not meaningful and this feature is
+ only available to mitigate timing attacks.
+
+ -- Function: void gcry_md_putc (gcry_md_hd_t H, int C)
+
+ Pass the byte in C to the digest object with handle H to update the
+ digest value. This is an efficient function, implemented as a
+ macro to buffer the data before an actual update.
+
+ The semantics of the hash functions do not provide for reading out
+intermediate message digests because the calculation must be finalized
+first. This finalization may for example include the number of bytes
+hashed in the message digest or some padding.
+
+ -- Function: void gcry_md_final (gcry_md_hd_t H)
+
+ Finalize the message digest calculation. This is not really needed
+ because 'gcry_md_read' and 'gcry_md_extract' do this implicitly.
+ After this has been done no further updates (by means of
+ 'gcry_md_write' or 'gcry_md_putc' should be done; However, to
+ mitigate timing attacks it is sometimes useful to keep on updating
+ the context after having stored away the actual digest. Only the
+ first call to this function has an effect. It is implemented as a
+ macro.
+
+ The way to read out the calculated message digest is by using the
+function:
+
+ -- Function: unsigned char * gcry_md_read (gcry_md_hd_t H, int ALGO)
+
+ 'gcry_md_read' returns the message digest after finalizing the
+ calculation. This function may be used as often as required but it
+ will always return the same value for one handle. The returned
+ message digest is allocated within the message context and
+ therefore valid until the handle is released or reset-ed (using
+ 'gcry_md_close' or 'gcry_md_reset' or it has been updated as a
+ mitigation measure against timing attacks. ALGO may be given as 0
+ to return the only enabled message digest or it may specify one of
+ the enabled algorithms. The function does return 'NULL' if the
+ requested algorithm has not been enabled.
+
+ The way to read output of extendable-output function is by using the
+function:
+
+ -- Function: gpg_err_code_t gcry_md_extract (gcry_md_hd_t H, int ALGO,
+ void *BUFFER, size_t LENGTH)
+
+ 'gcry_mac_read' returns output from extendable-output function.
+ This function may be used as often as required to generate more
+ output byte stream from the algorithm. Function extracts the new
+ output bytes to BUFFER of the length LENGTH. Buffer will be fully
+ populated with new output. ALGO may be given as 0 to return the
+ only enabled message digest or it may specify one of the enabled
+ algorithms. The function does return non-zero value if the
+ requested algorithm has not been enabled.
+
+ Because it is often necessary to get the message digest of blocks of
+memory, two fast convenience function are available for this task:
+
+ -- Function: gpg_err_code_t gcry_md_hash_buffers ( int ALGO,
+ unsigned int FLAGS, void *DIGEST, const gcry_buffer_t *IOV,
+ int IOVCNT )
+
+ 'gcry_md_hash_buffers' is a shortcut function to calculate a
+ message digest from several buffers. This function does not
+ require a context and immediately returns the message digest of the
+ data described by IOV and IOVCNT. DIGEST must be allocated by the
+ caller, large enough to hold the message digest yielded by the the
+ specified algorithm ALGO. This required size may be obtained by
+ using the function 'gcry_md_get_algo_dlen'.
+
+ IOV is an array of buffer descriptions with IOVCNT items. The
+ caller should zero out the structures in this array and for each
+ array item set the fields '.data' to the address of the data to be
+ hashed, '.len' to number of bytes to be hashed. If .OFF is also
+ set, the data is taken starting at .OFF bytes from the begin of the
+ buffer. The field '.size' is not used.
+
+ The only supported flag value for FLAGS is GCRY_MD_FLAG_HMAC which
+ turns this function into a HMAC function; the first item in IOV is
+ then used as the key.
+
+ On success the function returns 0 and stores the resulting hash or
+ MAC at DIGEST.
+
+ -- Function: void gcry_md_hash_buffer (int ALGO, void *DIGEST, const
+ void *BUFFER, size_t LENGTH);
+
+ 'gcry_md_hash_buffer' is a shortcut function to calculate a message
+ digest of a buffer. This function does not require a context and
+ immediately returns the message digest of the LENGTH bytes at
+ BUFFER. DIGEST must be allocated by the caller, large enough to
+ hold the message digest yielded by the the specified algorithm
+ ALGO. This required size may be obtained by using the function
+ 'gcry_md_get_algo_dlen'.
+
+ Note that in contrast to 'gcry_md_hash_buffers' this function will
+ abort the process if an unavailable algorithm is used.
+
+ Hash algorithms are identified by internal algorithm numbers (see
+'gcry_md_open' for a list). However, in most applications they are used
+by names, so two functions are available to map between string
+representations and hash algorithm identifiers.
+
+ -- Function: const char * gcry_md_algo_name (int ALGO)
+
+ Map the digest algorithm id ALGO to a string representation of the
+ algorithm name. For unknown algorithms this function returns the
+ string '"?"'. This function should not be used to test for the
+ availability of an algorithm.
+
+ -- Function: int gcry_md_map_name (const char *NAME)
+
+ Map the algorithm with NAME to a digest algorithm identifier.
+ Returns 0 if the algorithm name is not known. Names representing
+ ASN.1 object identifiers are recognized if the IETF dotted format
+ is used and the OID is prefixed with either "'oid.'" or "'OID.'".
+ For a list of supported OIDs, see the source code at 'cipher/md.c'.
+ This function should not be used to test for the availability of an
+ algorithm.
+
+ -- Function: gcry_error_t gcry_md_get_asnoid (int ALGO, void *BUFFER,
+ size_t *LENGTH)
+
+ Return an DER encoded ASN.1 OID for the algorithm ALGO in the user
+ allocated BUFFER. LENGTH must point to variable with the available
+ size of BUFFER and receives after return the actual size of the
+ returned OID. The returned error code may be 'GPG_ERR_TOO_SHORT' if
+ the provided buffer is to short to receive the OID; it is possible
+ to call the function with 'NULL' for BUFFER to have it only return
+ the required size. The function returns 0 on success.
+
+ To test whether an algorithm is actually available for use, the
+following macro should be used:
+
+ -- Function: gcry_error_t gcry_md_test_algo (int ALGO)
+
+ The macro returns 0 if the algorithm ALGO is available for use.
+
+ If the length of a message digest is not known, it can be retrieved
+using the following function:
+
+ -- Function: unsigned int gcry_md_get_algo_dlen (int ALGO)
+
+ Retrieve the length in bytes of the digest yielded by algorithm
+ ALGO. This is often used prior to 'gcry_md_read' to allocate
+ sufficient memory for the digest.
+
+ In some situations it might be hard to remember the algorithm used
+for the ongoing hashing. The following function might be used to get
+that information:
+
+ -- Function: int gcry_md_get_algo (gcry_md_hd_t H)
+
+ Retrieve the algorithm used with the handle H. Note that this does
+ not work reliable if more than one algorithm is enabled in H.
+
+ The following macro might also be useful:
+
+ -- Function: int gcry_md_is_secure (gcry_md_hd_t H)
+
+ This function returns true when the digest object H is allocated in
+ "secure memory"; i.e. H was created with the
+ 'GCRY_MD_FLAG_SECURE'.
+
+ -- Function: int gcry_md_is_enabled (gcry_md_hd_t H, int ALGO)
+
+ This function returns true when the algorithm ALGO has been enabled
+ for the digest object H.
+
+ Tracking bugs related to hashing is often a cumbersome task which
+requires to add a lot of printf statements into the code. Libgcrypt
+provides an easy way to avoid this. The actual data hashed can be
+written to files on request.
+
+ -- Function: void gcry_md_debug (gcry_md_hd_t H, const char *SUFFIX)
+
+ Enable debugging for the digest object with handle H. This creates
+ files named 'dbgmd-<n>.<string>' while doing the actual hashing.
+ SUFFIX is the string part in the filename. The number is a counter
+ incremented for each new hashing. The data in the file is the raw
+ data as passed to 'gcry_md_write' or 'gcry_md_putc'. If 'NULL' is
+ used for SUFFIX, the debugging is stopped and the file closed.
+ This is only rarely required because 'gcry_md_close' implicitly
+ stops debugging.
+
+\1f
+File: gcrypt.info, Node: Message Authentication Codes, Next: Key Derivation, Prev: Hashing, Up: Top
+
+8 Message Authentication Codes
+******************************
+
+Libgcrypt provides an easy and consistent to use interface for
+generating Message Authentication Codes (MAC). MAC generation is
+buffered and interface similar to the one used with hash algorithms.
+The programming model follows an open/process/close paradigm and is in
+that similar to other building blocks provided by Libgcrypt.
+
+* Menu:
+
+* Available MAC algorithms:: List of MAC algorithms supported by the library.
+* Working with MAC algorithms:: List of functions related to MAC algorithms.
+
+\1f
+File: gcrypt.info, Node: Available MAC algorithms, Next: Working with MAC algorithms, Up: Message Authentication Codes
+
+8.1 Available MAC algorithms
+============================
+
+'GCRY_MAC_NONE'
+ This is not a real algorithm but used by some functions as an error
+ return value. This constant is guaranteed to have the value '0'.
+
+'GCRY_MAC_HMAC_SHA256'
+ This is keyed-hash message authentication code (HMAC) message
+ authentication algorithm based on the SHA-256 hash algorithm.
+
+'GCRY_MAC_HMAC_SHA224'
+ This is HMAC message authentication algorithm based on the SHA-224
+ hash algorithm.
+
+'GCRY_MAC_HMAC_SHA512'
+ This is HMAC message authentication algorithm based on the SHA-512
+ hash algorithm.
+
+'GCRY_MAC_HMAC_SHA384'
+ This is HMAC message authentication algorithm based on the SHA-384
+ hash algorithm.
+
+'GCRY_MAC_HMAC_SHA3_256'
+ This is HMAC message authentication algorithm based on the SHA3-384
+ hash algorithm.
+
+'GCRY_MAC_HMAC_SHA3_224'
+ This is HMAC message authentication algorithm based on the SHA3-224
+ hash algorithm.
+
+'GCRY_MAC_HMAC_SHA3_512'
+ This is HMAC message authentication algorithm based on the SHA3-512
+ hash algorithm.
+
+'GCRY_MAC_HMAC_SHA3_384'
+ This is HMAC message authentication algorithm based on the SHA3-384
+ hash algorithm.
+
+'GCRY_MAC_HMAC_SHA1'
+ This is HMAC message authentication algorithm based on the SHA-1
+ hash algorithm.
+
+'GCRY_MAC_HMAC_MD5'
+ This is HMAC message authentication algorithm based on the MD5 hash
+ algorithm.
+
+'GCRY_MAC_HMAC_MD4'
+ This is HMAC message authentication algorithm based on the MD4 hash
+ algorithm.
+
+'GCRY_MAC_HMAC_RMD160'
+ This is HMAC message authentication algorithm based on the
+ RIPE-MD-160 hash algorithm.
+
+'GCRY_MAC_HMAC_WHIRLPOOL'
+ This is HMAC message authentication algorithm based on the
+ WHIRLPOOL hash algorithm.
+
+'GCRY_MAC_HMAC_GOSTR3411_94'
+ This is HMAC message authentication algorithm based on the GOST R
+ 34.11-94 hash algorithm.
+
+'GCRY_MAC_HMAC_STRIBOG256'
+ This is HMAC message authentication algorithm based on the 256-bit
+ hash algorithm described in GOST R 34.11-2012.
+
+'GCRY_MAC_HMAC_STRIBOG512'
+ This is HMAC message authentication algorithm based on the 512-bit
+ hash algorithm described in GOST R 34.11-2012.
+
+'GCRY_MAC_CMAC_AES'
+ This is CMAC (Cipher-based MAC) message authentication algorithm
+ based on the AES block cipher algorithm.
+
+'GCRY_MAC_CMAC_3DES'
+ This is CMAC message authentication algorithm based on the
+ three-key EDE Triple-DES block cipher algorithm.
+
+'GCRY_MAC_CMAC_CAMELLIA'
+ This is CMAC message authentication algorithm based on the Camellia
+ block cipher algorithm.
+
+'GCRY_MAC_CMAC_CAST5'
+ This is CMAC message authentication algorithm based on the
+ CAST128-5 block cipher algorithm.
+
+'GCRY_MAC_CMAC_BLOWFISH'
+ This is CMAC message authentication algorithm based on the Blowfish
+ block cipher algorithm.
+
+'GCRY_MAC_CMAC_TWOFISH'
+ This is CMAC message authentication algorithm based on the Twofish
+ block cipher algorithm.
+
+'GCRY_MAC_CMAC_SERPENT'
+ This is CMAC message authentication algorithm based on the Serpent
+ block cipher algorithm.
+
+'GCRY_MAC_CMAC_SEED'
+ This is CMAC message authentication algorithm based on the SEED
+ block cipher algorithm.
+
+'GCRY_MAC_CMAC_RFC2268'
+ This is CMAC message authentication algorithm based on the Ron's
+ Cipher 2 block cipher algorithm.
+
+'GCRY_MAC_CMAC_IDEA'
+ This is CMAC message authentication algorithm based on the IDEA
+ block cipher algorithm.
+
+'GCRY_MAC_CMAC_GOST28147'
+ This is CMAC message authentication algorithm based on the GOST
+ 28147-89 block cipher algorithm.
+
+'GCRY_MAC_GMAC_AES'
+ This is GMAC (GCM mode based MAC) message authentication algorithm
+ based on the AES block cipher algorithm.
+
+'GCRY_MAC_GMAC_CAMELLIA'
+ This is GMAC message authentication algorithm based on the Camellia
+ block cipher algorithm.
+
+'GCRY_MAC_GMAC_TWOFISH'
+ This is GMAC message authentication algorithm based on the Twofish
+ block cipher algorithm.
+
+'GCRY_MAC_GMAC_SERPENT'
+ This is GMAC message authentication algorithm based on the Serpent
+ block cipher algorithm.
+
+'GCRY_MAC_GMAC_SEED'
+ This is GMAC message authentication algorithm based on the SEED
+ block cipher algorithm.
+
+'GCRY_MAC_POLY1305'
+ This is plain Poly1305 message authentication algorithm, used with
+ one-time key.
+
+'GCRY_MAC_POLY1305_AES'
+ This is Poly1305-AES message authentication algorithm, used with
+ key and one-time nonce.
+
+'GCRY_MAC_POLY1305_CAMELLIA'
+ This is Poly1305-Camellia message authentication algorithm, used
+ with key and one-time nonce.
+
+'GCRY_MAC_POLY1305_TWOFISH'
+ This is Poly1305-Twofish message authentication algorithm, used
+ with key and one-time nonce.
+
+'GCRY_MAC_POLY1305_SERPENT'
+ This is Poly1305-Serpent message authentication algorithm, used
+ with key and one-time nonce.
+
+'GCRY_MAC_POLY1305_SEED'
+ This is Poly1305-SEED message authentication algorithm, used with
+ key and one-time nonce.
+
+\1f
+File: gcrypt.info, Node: Working with MAC algorithms, Prev: Available MAC algorithms, Up: Message Authentication Codes
+
+8.2 Working with MAC algorithms
+===============================
+
+To use most of these function it is necessary to create a context; this
+is done using:
+
+ -- Function: gcry_error_t gcry_mac_open (gcry_mac_hd_t *HD, int ALGO,
+ unsigned int FLAGS, gcry_ctx_t CTX)
+
+ Create a MAC object for algorithm ALGO. FLAGS may be given as an
+ bitwise OR of constants described below. HD is guaranteed to
+ either receive a valid handle or NULL. CTX is context object to
+ associate MAC object with. CTX maybe set to NULL.
+
+ For a list of supported algorithms, see *note Available MAC
+ algorithms::.
+
+ The flags allowed for MODE are:
+
+ 'GCRY_MAC_FLAG_SECURE'
+ Allocate all buffers and the resulting MAC in "secure memory".
+ Use this if the MAC data is highly confidential.
+
+ In order to use a handle for performing MAC algorithm operations, a
+'key' has to be set first:
+
+ -- Function: gcry_error_t gcry_mac_setkey (gcry_mac_hd_t H, const void
+ *KEY, size_t KEYLEN)
+
+ Set the MAC key to the value of KEY of length KEYLEN bytes. With
+ HMAC algorithms, there is no restriction on the length of the key.
+ With CMAC algorithms, the length of the key is restricted to those
+ supported by the underlying block cipher.
+
+ GMAC algorithms and Poly1305-with-cipher algorithms need
+initialization vector to be set, which can be performed with function:
+
+ -- Function: gcry_error_t gcry_mac_setiv (gcry_mac_hd_t H, const void
+ *IV, size_t IVLEN)
+
+ Set the IV to the value of IV of length IVLEN bytes.
+
+ After you are done with the MAC calculation, you should release the
+resources by using:
+
+ -- Function: void gcry_mac_close (gcry_mac_hd_t H)
+
+ Release all resources of MAC context H. H should not be used after
+ a call to this function. A 'NULL' passed as H is ignored. The
+ function also clears all sensitive information associated with this
+ handle.
+
+ Often you have to do several MAC operations using the same algorithm.
+To avoid the overhead of creating and releasing context, a reset
+function is provided:
+
+ -- Function: gcry_error_t gcry_mac_reset (gcry_mac_hd_t H)
+
+ Reset the current context to its initial state. This is
+ effectively identical to a close followed by an open and setting
+ same key.
+
+ Note that gcry_mac_reset is implemented as a macro.
+
+ Now that we have prepared everything to calculate MAC, it is time to
+see how it is actually done.
+
+ -- Function: gcry_error_t gcry_mac_write (gcry_mac_hd_t H, const void
+ *BUFFER, size_t LENGTH)
+
+ Pass LENGTH bytes of the data in BUFFER to the MAC object with
+ handle H to update the MAC values. If this function is used after
+ the context has been finalized, it will keep on pushing the data
+ through the algorithm specific transform function and thereby
+ change the context; however the results are not meaningful and this
+ feature is only available to mitigate timing attacks.
+
+ The way to read out the calculated MAC is by using the function:
+
+ -- Function: gcry_error_t gcry_mac_read (gcry_mac_hd_t H, void *BUFFER,
+ size_t *LENGTH)
+
+ 'gcry_mac_read' returns the MAC after finalizing the calculation.
+ Function copies the resulting MAC value to BUFFER of the length
+ LENGTH. If LENGTH is larger than length of resulting MAC value,
+ then length of MAC is returned through LENGTH.
+
+ To compare existing MAC value with recalculated MAC, one is to use
+the function:
+
+ -- Function: gcry_error_t gcry_mac_verify (gcry_mac_hd_t H, void
+ *BUFFER, size_t LENGTH)
+
+ 'gcry_mac_verify' finalizes MAC calculation and compares result
+ with LENGTH bytes of data in BUFFER. Error code 'GPG_ERR_CHECKSUM'
+ is returned if the MAC value in the buffer BUFFER does not match
+ the MAC calculated in object H.
+
+ In some situations it might be hard to remember the algorithm used
+for the MAC calculation. The following function might be used to get
+that information:
+
+ -- Function: int gcry_mac_get_algo (gcry_mac_hd_t H)
+
+ Retrieve the algorithm used with the handle H.
+
+ MAC algorithms are identified by internal algorithm numbers (see
+'gcry_mac_open' for a list). However, in most applications they are
+used by names, so two functions are available to map between string
+representations and MAC algorithm identifiers.
+
+ -- Function: const char * gcry_mac_algo_name (int ALGO)
+
+ Map the MAC algorithm id ALGO to a string representation of the
+ algorithm name. For unknown algorithms this function returns the
+ string '"?"'. This function should not be used to test for the
+ availability of an algorithm.
+
+ -- Function: int gcry_mac_map_name (const char *NAME)
+
+ Map the algorithm with NAME to a MAC algorithm identifier. Returns
+ 0 if the algorithm name is not known. This function should not be
+ used to test for the availability of an algorithm.
+
+ To test whether an algorithm is actually available for use, the
+following macro should be used:
+
+ -- Function: gcry_error_t gcry_mac_test_algo (int ALGO)
+
+ The macro returns 0 if the MAC algorithm ALGO is available for use.
+
+ If the length of a message digest is not known, it can be retrieved
+using the following function:
+
+ -- Function: unsigned int gcry_mac_get_algo_maclen (int ALGO)
+
+ Retrieve the length in bytes of the MAC yielded by algorithm ALGO.
+ This is often used prior to 'gcry_mac_read' to allocate sufficient
+ memory for the MAC value. On error '0' is returned.
+
+ -- Function: unsigned int gcry_mac_get_algo_keylen (ALGO)
+
+ This function returns length of the key for MAC algorithm ALGO. If
+ the algorithm supports multiple key lengths, the default supported
+ key length is returned. On error '0' is returned. The key length
+ is returned as number of octets.
+
+\1f
+File: gcrypt.info, Node: Key Derivation, Next: Random Numbers, Prev: Message Authentication Codes, Up: Top
+
+9 Key Derivation
+****************
+
+Libgcypt provides a general purpose function to derive keys from
+strings.
+
+ -- Function: gpg_error_t gcry_kdf_derive ( const void *PASSPHRASE,
+ size_t PASSPHRASELEN, int ALGO, int SUBALGO, const void *SALT,
+ size_t SALTLEN, unsigned long ITERATIONS, size_t KEYSIZE,
+ void *KEYBUFFER )
+
+ Derive a key from a passphrase. KEYSIZE gives the requested size
+ of the keys in octets. KEYBUFFER is a caller provided buffer
+ filled on success with the derived key. The input passphrase is
+ taken from PASSPHRASE which is an arbitrary memory buffer of
+ PASSPHRASELEN octets. ALGO specifies the KDF algorithm to use; see
+ below. SUBALGO specifies an algorithm used internally by the KDF
+ algorithms; this is usually a hash algorithm but certain KDF
+ algorithms may use it differently. SALT is a salt of length
+ SALTLEN octets, as needed by most KDF algorithms. ITERATIONS is a
+ positive integer parameter to most KDFs.
+
+ On success 0 is returned; on failure an error code.
+
+ Currently supported KDFs (parameter ALGO):
+
+ 'GCRY_KDF_SIMPLE_S2K'
+ The OpenPGP simple S2K algorithm (cf. RFC4880). Its use is
+ strongly deprecated. SALT and ITERATIONS are not needed and
+ may be passed as 'NULL'/'0'.
+
+ 'GCRY_KDF_SALTED_S2K'
+ The OpenPGP salted S2K algorithm (cf. RFC4880). Usually not
+ used. ITERATIONS is not needed and may be passed as '0'.
+ SALTLEN must be given as 8.
+
+ 'GCRY_KDF_ITERSALTED_S2K'
+ The OpenPGP iterated+salted S2K algorithm (cf. RFC4880).
+ This is the default for most OpenPGP applications. SALTLEN
+ must be given as 8. Note that OpenPGP defines a special
+ encoding of the ITERATIONS; however this function takes the
+ plain decoded iteration count.
+
+ 'GCRY_KDF_PBKDF2'
+ The PKCS#5 Passphrase Based Key Derivation Function number 2.
+
+ 'GCRY_KDF_SCRYPT'
+ The SCRYPT Key Derivation Function. The subalgorithm is used
+ to specify the CPU/memory cost parameter N, and the number of
+ iterations is used for the parallelization parameter p. The
+ block size is fixed at 8 in the current implementation.
+
+\1f
+File: gcrypt.info, Node: Random Numbers, Next: S-expressions, Prev: Key Derivation, Up: Top
+
+10 Random Numbers
+*****************
+
+* Menu:
+
+* Quality of random numbers:: Libgcrypt uses different quality levels.
+* Retrieving random numbers:: How to retrieve random numbers.
+
+\1f
+File: gcrypt.info, Node: Quality of random numbers, Next: Retrieving random numbers, Up: Random Numbers
+
+10.1 Quality of random numbers
+==============================
+
+Libgcypt offers random numbers of different quality levels:
+
+ -- Data type: gcry_random_level_t
+ The constants for the random quality levels are of this enum type.
+
+'GCRY_WEAK_RANDOM'
+ For all functions, except for 'gcry_mpi_randomize', this level maps
+ to GCRY_STRONG_RANDOM. If you do not want this, consider using
+ 'gcry_create_nonce'.
+'GCRY_STRONG_RANDOM'
+ Use this level for session keys and similar purposes.
+'GCRY_VERY_STRONG_RANDOM'
+ Use this level for long term key material.
+
+\1f
+File: gcrypt.info, Node: Retrieving random numbers, Prev: Quality of random numbers, Up: Random Numbers
+
+10.2 Retrieving random numbers
+==============================
+
+ -- Function: void gcry_randomize (unsigned char *BUFFER, size_t LENGTH,
+ enum gcry_random_level LEVEL)
+
+ Fill BUFFER with LENGTH random bytes using a random quality as
+ defined by LEVEL.
+
+ -- Function: void * gcry_random_bytes (size_t NBYTES, enum
+ gcry_random_level LEVEL)
+
+ Convenience function to allocate a memory block consisting of
+ NBYTES fresh random bytes using a random quality as defined by
+ LEVEL.
+
+ -- Function: void * gcry_random_bytes_secure (size_t NBYTES, enum
+ gcry_random_level LEVEL)
+
+ Convenience function to allocate a memory block consisting of
+ NBYTES fresh random bytes using a random quality as defined by
+ LEVEL. This function differs from 'gcry_random_bytes' in that the
+ returned buffer is allocated in a "secure" area of the memory.
+
+ -- Function: void gcry_create_nonce (unsigned char *BUFFER, size_t
+ LENGTH)
+
+ Fill BUFFER with LENGTH unpredictable bytes. This is commonly
+ called a nonce and may also be used for initialization vectors and
+ padding. This is an extra function nearly independent of the other
+ random function for 3 reasons: It better protects the regular
+ random generator's internal state, provides better performance and
+ does not drain the precious entropy pool.
+
+\1f
+File: gcrypt.info, Node: S-expressions, Next: MPI library, Prev: Random Numbers, Up: Top
+
+11 S-expressions
+****************
+
+S-expressions are used by the public key functions to pass complex data
+structures around. These LISP like objects are used by some
+cryptographic protocols (cf. RFC-2692) and Libgcrypt provides functions
+to parse and construct them. For detailed information, see 'Ron Rivest,
+code and description of S-expressions,
+<http://theory.lcs.mit.edu/~rivest/sexp.html>'.
+
+* Menu:
+
+* Data types for S-expressions:: Data types related with S-expressions.
+* Working with S-expressions:: How to work with S-expressions.
+
+\1f
+File: gcrypt.info, Node: Data types for S-expressions, Next: Working with S-expressions, Up: S-expressions
+
+11.1 Data types for S-expressions
+=================================
+
+ -- Data type: gcry_sexp_t
+ The 'gcry_sexp_t' type describes an object with the Libgcrypt
+ internal representation of an S-expression.
+
+\1f
+File: gcrypt.info, Node: Working with S-expressions, Prev: Data types for S-expressions, Up: S-expressions
+
+11.2 Working with S-expressions
+===============================
+
+There are several functions to create an Libgcrypt S-expression object
+from its external representation or from a string template. There is
+also a function to convert the internal representation back into one of
+the external formats:
+
+ -- Function: gcry_error_t gcry_sexp_new (gcry_sexp_t *R_SEXP,
+ const void *BUFFER, size_t LENGTH, int AUTODETECT)
+
+ This is the generic function to create an new S-expression object
+ from its external representation in BUFFER of LENGTH bytes. On
+ success the result is stored at the address given by R_SEXP. With
+ AUTODETECT set to 0, the data in BUFFER is expected to be in
+ canonized format, with AUTODETECT set to 1 the parses any of the
+ defined external formats. If BUFFER does not hold a valid
+ S-expression an error code is returned and R_SEXP set to 'NULL'.
+ Note that the caller is responsible for releasing the newly
+ allocated S-expression using 'gcry_sexp_release'.
+
+ -- Function: gcry_error_t gcry_sexp_create (gcry_sexp_t *R_SEXP,
+ void *BUFFER, size_t LENGTH, int AUTODETECT,
+ void (*FREEFNC)(void*))
+
+ This function is identical to 'gcry_sexp_new' but has an extra
+ argument FREEFNC, which, when not set to 'NULL', is expected to be
+ a function to release the BUFFER; most likely the standard 'free'
+ function is used for this argument. This has the effect of
+ transferring the ownership of BUFFER to the created object in
+ R_SEXP. The advantage of using this function is that Libgcrypt
+ might decide to directly use the provided buffer and thus avoid
+ extra copying.
+
+ -- Function: gcry_error_t gcry_sexp_sscan (gcry_sexp_t *R_SEXP,
+ size_t *ERROFF, const char *BUFFER, size_t LENGTH)
+
+ This is another variant of the above functions. It behaves nearly
+ identical but provides an ERROFF argument which will receive the
+ offset into the buffer where the parsing stopped on error.
+
+ -- Function: gcry_error_t gcry_sexp_build (gcry_sexp_t *R_SEXP,
+ size_t *ERROFF, const char *FORMAT, ...)
+
+ This function creates an internal S-expression from the string
+ template FORMAT and stores it at the address of R_SEXP. If there
+ is a parsing error, the function returns an appropriate error code
+ and stores the offset into FORMAT where the parsing stopped in
+ ERROFF. The function supports a couple of printf-like formatting
+ characters and expects arguments for some of these escape sequences
+ right after FORMAT. The following format characters are defined:
+
+ '%m'
+ The next argument is expected to be of type 'gcry_mpi_t' and a
+ copy of its value is inserted into the resulting S-expression.
+ The MPI is stored as a signed integer.
+ '%M'
+ The next argument is expected to be of type 'gcry_mpi_t' and a
+ copy of its value is inserted into the resulting S-expression.
+ The MPI is stored as an unsigned integer.
+ '%s'
+ The next argument is expected to be of type 'char *' and that
+ string is inserted into the resulting S-expression.
+ '%d'
+ The next argument is expected to be of type 'int' and its
+ value is inserted into the resulting S-expression.
+ '%u'
+ The next argument is expected to be of type 'unsigned int' and
+ its value is inserted into the resulting S-expression.
+ '%b'
+ The next argument is expected to be of type 'int' directly
+ followed by an argument of type 'char *'. This represents a
+ buffer of given length to be inserted into the resulting
+ S-expression.
+ '%S'
+ The next argument is expected to be of type 'gcry_sexp_t' and
+ a copy of that S-expression is embedded in the resulting
+ S-expression. The argument needs to be a regular
+ S-expression, starting with a parenthesis.
+
+ No other format characters are defined and would return an error.
+ Note that the format character '%%' does not exists, because a
+ percent sign is not a valid character in an S-expression.
+
+ -- Function: void gcry_sexp_release (gcry_sexp_t SEXP)
+
+ Release the S-expression object SEXP. If the S-expression is
+ stored in secure memory it explicitly zeroises that memory; note
+ that this is done in addition to the zeroisation always done when
+ freeing secure memory.
+
+The next 2 functions are used to convert the internal representation
+back into a regular external S-expression format and to show the
+structure for debugging.
+
+ -- Function: size_t gcry_sexp_sprint (gcry_sexp_t SEXP, int MODE,
+ char *BUFFER, size_t MAXLENGTH)
+
+ Copies the S-expression object SEXP into BUFFER using the format
+ specified in MODE. MAXLENGTH must be set to the allocated length
+ of BUFFER. The function returns the actual length of valid bytes
+ put into BUFFER or 0 if the provided buffer is too short. Passing
+ 'NULL' for BUFFER returns the required length for BUFFER. For
+ convenience reasons an extra byte with value 0 is appended to the
+ buffer.
+
+ The following formats are supported:
+
+ 'GCRYSEXP_FMT_DEFAULT'
+ Returns a convenient external S-expression representation.
+
+ 'GCRYSEXP_FMT_CANON'
+ Return the S-expression in canonical format.
+
+ 'GCRYSEXP_FMT_BASE64'
+ Not currently supported.
+
+ 'GCRYSEXP_FMT_ADVANCED'
+ Returns the S-expression in advanced format.
+
+ -- Function: void gcry_sexp_dump (gcry_sexp_t SEXP)
+
+ Dumps SEXP in a format suitable for debugging to Libgcrypt's
+ logging stream.
+
+Often canonical encoding is used in the external representation. The
+following function can be used to check for valid encoding and to learn
+the length of the S-expression.
+
+ -- Function: size_t gcry_sexp_canon_len (const unsigned char *BUFFER,
+ size_t LENGTH, size_t *ERROFF, int *ERRCODE)
+
+ Scan the canonical encoded BUFFER with implicit length values and
+ return the actual length this S-expression uses. For a valid
+ S-expression it should never return 0. If LENGTH is not 0, the
+ maximum length to scan is given; this can be used for syntax checks
+ of data passed from outside. ERRCODE and ERROFF may both be passed
+ as 'NULL'.
+
+There are functions to parse S-expressions and retrieve elements:
+
+ -- Function: gcry_sexp_t gcry_sexp_find_token (const gcry_sexp_t LIST,
+ const char *TOKEN, size_t TOKLEN)
+
+ Scan the S-expression for a sublist with a type (the car of the
+ list) matching the string TOKEN. If TOKLEN is not 0, the token is
+ assumed to be raw memory of this length. The function returns a
+ newly allocated S-expression consisting of the found sublist or
+ 'NULL' when not found.
+
+ -- Function: int gcry_sexp_length (const gcry_sexp_t LIST)
+
+ Return the length of the LIST. For a valid S-expression this
+ should be at least 1.
+
+ -- Function: gcry_sexp_t gcry_sexp_nth (const gcry_sexp_t LIST,
+ int NUMBER)
+
+ Create and return a new S-expression from the element with index
+ NUMBER in LIST. Note that the first element has the index 0. If
+ there is no such element, 'NULL' is returned.
+
+ -- Function: gcry_sexp_t gcry_sexp_car (const gcry_sexp_t LIST)
+
+ Create and return a new S-expression from the first element in
+ LIST; this is called the "type" and should always exist per
+ S-expression specification and in general be a string. 'NULL' is
+ returned in case of a problem.
+
+ -- Function: gcry_sexp_t gcry_sexp_cdr (const gcry_sexp_t LIST)
+
+ Create and return a new list form all elements except for the first
+ one. Note that this function may return an invalid S-expression
+ because it is not guaranteed, that the type exists and is a string.
+ However, for parsing a complex S-expression it might be useful for
+ intermediate lists. Returns 'NULL' on error.
+
+ -- Function: const char * gcry_sexp_nth_data (const gcry_sexp_t LIST,
+ int NUMBER, size_t *DATALEN)
+
+ This function is used to get data from a LIST. A pointer to the
+ actual data with index NUMBER is returned and the length of this
+ data will be stored to DATALEN. If there is no data at the given
+ index or the index represents another list, 'NULL' is returned.
+ *Caution:* The returned pointer is valid as long as LIST is not
+ modified or released.
+
+ Here is an example on how to extract and print the surname (Meier)
+ from the S-expression '(Name Otto Meier (address Burgplatz 3))':
+
+ size_t len;
+ const char *name;
+
+ name = gcry_sexp_nth_data (list, 2, &len);
+ printf ("my name is %.*s\n", (int)len, name);
+
+ -- Function: void * gcry_sexp_nth_buffer (const gcry_sexp_t LIST,
+ int NUMBER, size_t *RLENGTH)
+
+ This function is used to get data from a LIST. A malloced buffer
+ with the actual data at list index NUMBER is returned and the
+ length of this buffer will be stored to RLENGTH. If there is no
+ data at the given index or the index represents another list,
+ 'NULL' is returned. The caller must release the result using
+ 'gcry_free'.
+
+ Here is an example on how to extract and print the CRC value from
+ the S-expression '(hash crc32 #23ed00d7)':
+
+ size_t len;
+ char *value;
+
+ value = gcry_sexp_nth_buffer (list, 2, &len);
+ if (value)
+ fwrite (value, len, 1, stdout);
+ gcry_free (value);
+
+ -- Function: char * gcry_sexp_nth_string (gcry_sexp_t LIST, int NUMBER)
+
+ This function is used to get and convert data from a LIST. The
+ data is assumed to be a Nul terminated string. The caller must
+ release this returned value using 'gcry_free'. If there is no data
+ at the given index, the index represents a list or the value can't
+ be converted to a string, 'NULL' is returned.
+
+ -- Function: gcry_mpi_t gcry_sexp_nth_mpi (gcry_sexp_t LIST,
+ int NUMBER, int MPIFMT)
+
+ This function is used to get and convert data from a LIST. This
+ data is assumed to be an MPI stored in the format described by
+ MPIFMT and returned as a standard Libgcrypt MPI. The caller must
+ release this returned value using 'gcry_mpi_release'. If there is
+ no data at the given index, the index represents a list or the
+ value can't be converted to an MPI, 'NULL' is returned. If you use
+ this function to parse results of a public key function, you most
+ likely want to use 'GCRYMPI_FMT_USG'.
+
+ -- Function: gpg_error_t gcry_sexp_extract_param ( gcry_sexp_t SEXP,
+ const char *PATH, const char *LIST, ...)
+
+ Extract parameters from an S-expression using a list of parameter
+ names. The names of these parameters are specified in LIST. White
+ space between the parameter names are ignored. Some special
+ characters may be given to control the conversion:
+
+ '+'
+ Switch to unsigned integer format (GCRYMPI_FMT_USG). This is
+ the default mode.
+ '-'
+ Switch to standard signed format (GCRYMPI_FMT_STD).
+ '/'
+ Switch to opaque MPI format. The resulting MPIs may not be
+ used for computations; see 'gcry_mpi_get_opaque' for details.
+ '&'
+ Switch to buffer descriptor mode. See below for details.
+ '?'
+ If immediately following a parameter letter (no white space
+ allowed), that parameter is considered optional.
+
+ In general parameter names are single letters. To use a string for
+ a parameter name, enclose the name in single quotes.
+
+ Unless in buffer descriptor mode for each parameter name a pointer
+ to an 'gcry_mpi_t' variable is expected that must be set to 'NULL'
+ prior to invoking this function, and finally a 'NULL' is expected.
+ For example
+
+ _gcry_sexp_extract_param (key, NULL, "n/x+e d-'foo'",
+ &mpi_n, &mpi_x, &mpi_e, &mpi_foo, NULL)
+
+ stores the parameter 'n' from KEY as an unsigned MPI into MPI_N,
+ the parameter 'x' as an opaque MPI into MPI_X, the parameter 'e'
+ again as an unsigned MPI into MPI_E, and the parameter 'foo' as a
+ signed MPI.
+
+ PATH is an optional string used to locate a token. The exclamation
+ mark separated tokens are used via 'gcry_sexp_find_token' to find a
+ start point inside the S-expression.
+
+ In buffer descriptor mode a pointer to a 'gcry_buffer_t' descriptor
+ is expected instead of a pointer to an MPI. The caller may use two
+ different operation modes here: If the DATA field of the provided
+ descriptor is 'NULL', the function allocates a new buffer and
+ stores it at DATA; the other fields are set accordingly with OFF
+ set to 0. If DATA is not 'NULL', the function assumes that the
+ DATA, SIZE, and OFF fields specify a buffer where to but the value
+ of the respective parameter; on return the LEN field receives the
+ number of bytes copied to that buffer; in case the buffer is too
+ small, the function immediately returns with an error code (and LEN
+ is set to 0).
+
+ The function returns 0 on success. On error an error code is
+ returned, all passed MPIs that might have been allocated up to this
+ point are deallocated and set to 'NULL', and all passed buffers are
+ either truncated if the caller supplied the buffer, or deallocated
+ if the function allocated the buffer.
+
+\1f
+File: gcrypt.info, Node: MPI library, Next: Prime numbers, Prev: S-expressions, Up: Top
+
+12 MPI library
+**************
+
+* Menu:
+
+* Data types:: MPI related data types.
+* Basic functions:: First steps with MPI numbers.
+* MPI formats:: External representation of MPIs.
+* Calculations:: Performing MPI calculations.
+* Comparisons:: How to compare MPI values.
+* Bit manipulations:: How to access single bits of MPI values.
+* EC functions:: Elliptic curve related functions.
+* Miscellaneous:: Miscellaneous MPI functions.
+
+Public key cryptography is based on mathematics with large numbers. To
+implement the public key functions, a library for handling these large
+numbers is required. Because of the general usefulness of such a
+library, its interface is exposed by Libgcrypt. In the context of
+Libgcrypt and in most other applications, these large numbers are called
+MPIs (multi-precision-integers).
+
+\1f
+File: gcrypt.info, Node: Data types, Next: Basic functions, Up: MPI library
+
+12.1 Data types
+===============
+
+ -- Data type: gcry_mpi_t
+ This type represents an object to hold an MPI.
+
+ -- Data type: gcry_mpi_point_t
+ This type represents an object to hold a point for elliptic curve
+ math.
+
+\1f
+File: gcrypt.info, Node: Basic functions, Next: MPI formats, Prev: Data types, Up: MPI library
+
+12.2 Basic functions
+====================
+
+To work with MPIs, storage must be allocated and released for the
+numbers. This can be done with one of these functions:
+
+ -- Function: gcry_mpi_t gcry_mpi_new (unsigned int NBITS)
+
+ Allocate a new MPI object, initialize it to 0 and initially
+ allocate enough memory for a number of at least NBITS. This
+ pre-allocation is only a small performance issue and not actually
+ necessary because Libgcrypt automatically re-allocates the required
+ memory.
+
+ -- Function: gcry_mpi_t gcry_mpi_snew (unsigned int NBITS)
+
+ This is identical to 'gcry_mpi_new' but allocates the MPI in the so
+ called "secure memory" which in turn will take care that all
+ derived values will also be stored in this "secure memory". Use
+ this for highly confidential data like private key parameters.
+
+ -- Function: gcry_mpi_t gcry_mpi_copy (const gcry_mpi_t A)
+
+ Create a new MPI as the exact copy of A but with the constant and
+ immutable flags cleared.
+
+ -- Function: void gcry_mpi_release (gcry_mpi_t A)
+
+ Release the MPI A and free all associated resources. Passing
+ 'NULL' is allowed and ignored. When a MPI stored in the "secure
+ memory" is released, that memory gets wiped out immediately.
+
+The simplest operations are used to assign a new value to an MPI:
+
+ -- Function: gcry_mpi_t gcry_mpi_set (gcry_mpi_t W, const gcry_mpi_t U)
+
+ Assign the value of U to W and return W. If 'NULL' is passed for
+ W, a new MPI is allocated, set to the value of U and returned.
+
+ -- Function: gcry_mpi_t gcry_mpi_set_ui (gcry_mpi_t W, unsigned long U)
+
+ Assign the value of U to W and return W. If 'NULL' is passed for
+ W, a new MPI is allocated, set to the value of U and returned.
+ This function takes an 'unsigned int' as type for U and thus it is
+ only possible to set W to small values (usually up to the word size
+ of the CPU).
+
+ -- Function: void gcry_mpi_swap (gcry_mpi_t A, gcry_mpi_t B)
+
+ Swap the values of A and B.
+
+ -- Function: void gcry_mpi_snatch (gcry_mpi_t W, const gcry_mpi_t U)
+
+ Set U into W and release U. If W is 'NULL' only U will be
+ released.
+
+ -- Function: void gcry_mpi_neg (gcry_mpi_t W, gcry_mpi_t U)
+
+ Set the sign of W to the negative of U.
+
+ -- Function: void gcry_mpi_abs (gcry_mpi_t W)
+
+ Clear the sign of W.
+
+\1f
+File: gcrypt.info, Node: MPI formats, Next: Calculations, Prev: Basic functions, Up: MPI library
+
+12.3 MPI formats
+================
+
+The following functions are used to convert between an external
+representation of an MPI and the internal one of Libgcrypt.
+
+ -- Function: gcry_error_t gcry_mpi_scan (gcry_mpi_t *R_MPI,
+ enum gcry_mpi_format FORMAT, const unsigned char *BUFFER,
+ size_t BUFLEN, size_t *NSCANNED)
+
+ Convert the external representation of an integer stored in BUFFER
+ with a length of BUFLEN into a newly created MPI returned which
+ will be stored at the address of R_MPI. For certain formats the
+ length argument is not required and should be passed as '0'. A
+ BUFLEN larger than 16 MiByte will be rejected. After a successful
+ operation the variable NSCANNED receives the number of bytes
+ actually scanned unless NSCANNED was given as 'NULL'. FORMAT
+ describes the format of the MPI as stored in BUFFER:
+
+ 'GCRYMPI_FMT_STD'
+ 2-complement stored without a length header. Note that
+ 'gcry_mpi_print' stores a '0' as a string of zero length.
+
+ 'GCRYMPI_FMT_PGP'
+ As used by OpenPGP (only defined as unsigned). This is
+ basically 'GCRYMPI_FMT_STD' with a 2 byte big endian length
+ header. A length header indicating a length of more than
+ 16384 is not allowed.
+
+ 'GCRYMPI_FMT_SSH'
+ As used in the Secure Shell protocol. This is
+ 'GCRYMPI_FMT_STD' with a 4 byte big endian header.
+
+ 'GCRYMPI_FMT_HEX'
+ Stored as a string with each byte of the MPI encoded as 2 hex
+ digits. Negative numbers are prefix with a minus sign and in
+ addition the high bit is always zero to make clear that an
+ explicit sign ist used. When using this format, BUFLEN must
+ be zero.
+
+ 'GCRYMPI_FMT_USG'
+ Simple unsigned integer.
+
+ Note that all of the above formats store the integer in big-endian
+ format (MSB first).
+
+ -- Function: gcry_error_t gcry_mpi_print (enum gcry_mpi_format FORMAT,
+ unsigned char *BUFFER, size_t BUFLEN, size_t *NWRITTEN,
+ const gcry_mpi_t A)
+
+ Convert the MPI A into an external representation described by
+ FORMAT (see above) and store it in the provided BUFFER which has a
+ usable length of at least the BUFLEN bytes. If NWRITTEN is not
+ NULL, it will receive the number of bytes actually stored in BUFFER
+ after a successful operation.
+
+ -- Function: gcry_error_t gcry_mpi_aprint (enum gcry_mpi_format FORMAT,
+ unsigned char **BUFFER, size_t *NBYTES, const gcry_mpi_t A)
+
+ Convert the MPI A into an external representation described by
+ FORMAT (see above) and store it in a newly allocated buffer which
+ address will be stored in the variable BUFFER points to. The
+ number of bytes stored in this buffer will be stored in the
+ variable NBYTES points to, unless NBYTES is 'NULL'.
+
+ Even if NBYTES is zero, the function allocates at least one byte
+ and store a zero there. Thus with formats 'GCRYMPI_FMT_STD' and
+ 'GCRYMPI_FMT_USG' the caller may safely set a returned length of 0
+ to 1 to represent a zero as a 1 byte string.
+
+ -- Function: void gcry_mpi_dump (const gcry_mpi_t A)
+
+ Dump the value of A in a format suitable for debugging to
+ Libgcrypt's logging stream. Note that one leading space but no
+ trailing space or linefeed will be printed. It is okay to pass
+ 'NULL' for A.
+
+\1f
+File: gcrypt.info, Node: Calculations, Next: Comparisons, Prev: MPI formats, Up: MPI library
+
+12.4 Calculations
+=================
+
+Basic arithmetic operations:
+
+ -- Function: void gcry_mpi_add (gcry_mpi_t W, gcry_mpi_t U,
+ gcry_mpi_t V)
+
+ W = U + V.
+
+ -- Function: void gcry_mpi_add_ui (gcry_mpi_t W, gcry_mpi_t U,
+ unsigned long V)
+
+ W = U + V. Note that V is an unsigned integer.
+
+ -- Function: void gcry_mpi_addm (gcry_mpi_t W, gcry_mpi_t U,
+ gcry_mpi_t V, gcry_mpi_t M)
+
+ W = U + V \bmod M.
+
+ -- Function: void gcry_mpi_sub (gcry_mpi_t W, gcry_mpi_t U,
+ gcry_mpi_t V)
+
+ W = U - V.
+
+ -- Function: void gcry_mpi_sub_ui (gcry_mpi_t W, gcry_mpi_t U,
+ unsigned long V)
+
+ W = U - V. V is an unsigned integer.
+
+ -- Function: void gcry_mpi_subm (gcry_mpi_t W, gcry_mpi_t U,
+ gcry_mpi_t V, gcry_mpi_t M)
+
+ W = U - V \bmod M.
+
+ -- Function: void gcry_mpi_mul (gcry_mpi_t W, gcry_mpi_t U,
+ gcry_mpi_t V)
+
+ W = U * V.
+
+ -- Function: void gcry_mpi_mul_ui (gcry_mpi_t W, gcry_mpi_t U,
+ unsigned long V)
+
+ W = U * V. V is an unsigned integer.
+
+ -- Function: void gcry_mpi_mulm (gcry_mpi_t W, gcry_mpi_t U,
+ gcry_mpi_t V, gcry_mpi_t M)
+
+ W = U * V \bmod M.
+
+ -- Function: void gcry_mpi_mul_2exp (gcry_mpi_t W, gcry_mpi_t U,
+ unsigned long E)
+
+ W = U * 2^e.
+
+ -- Function: void gcry_mpi_div (gcry_mpi_t Q, gcry_mpi_t R,
+ gcry_mpi_t DIVIDEND, gcry_mpi_t DIVISOR, int ROUND)
+
+ Q = DIVIDEND / DIVISOR, R = DIVIDEND \bmod DIVISOR. Q and R may be
+ passed as 'NULL'. ROUND should be negative or 0.
+
+ -- Function: void gcry_mpi_mod (gcry_mpi_t R, gcry_mpi_t DIVIDEND,
+ gcry_mpi_t DIVISOR)
+
+ R = DIVIDEND \bmod DIVISOR.
+
+ -- Function: void gcry_mpi_powm (gcry_mpi_t W, const gcry_mpi_t B,
+ const gcry_mpi_t E, const gcry_mpi_t M)
+
+ W = B^e \bmod M.
+
+ -- Function: int gcry_mpi_gcd (gcry_mpi_t G, gcry_mpi_t A,
+ gcry_mpi_t B)
+
+ Set G to the greatest common divisor of A and B. Return true if
+ the G is 1.
+
+ -- Function: int gcry_mpi_invm (gcry_mpi_t X, gcry_mpi_t A,
+ gcry_mpi_t M)
+
+ Set X to the multiplicative inverse of A \bmod M. Return true if
+ the inverse exists.
+
+\1f
+File: gcrypt.info, Node: Comparisons, Next: Bit manipulations, Prev: Calculations, Up: MPI library
+
+12.5 Comparisons
+================
+
+The next 2 functions are used to compare MPIs:
+
+ -- Function: int gcry_mpi_cmp (const gcry_mpi_t U, const gcry_mpi_t V)
+
+ Compare the multi-precision-integers number U and V returning 0 for
+ equality, a positive value for U > V and a negative for U < V. If
+ both numbers are opaque values (cf, gcry_mpi_set_opaque) the
+ comparison is done by checking the bit sizes using memcmp. If only
+ one number is an opaque value, the opaque value is less than the
+ other number.
+
+ -- Function: int gcry_mpi_cmp_ui (const gcry_mpi_t U, unsigned long V)
+
+ Compare the multi-precision-integers number U with the unsigned
+ integer V returning 0 for equality, a positive value for U > V and
+ a negative for U < V.
+
+ -- Function: int gcry_mpi_is_neg (const gcry_mpi_t A)
+
+ Return 1 if A is less than zero; return 0 if zero or positive.
+
+\1f
+File: gcrypt.info, Node: Bit manipulations, Next: EC functions, Prev: Comparisons, Up: MPI library
+
+12.6 Bit manipulations
+======================
+
+There are a couple of functions to get information on arbitrary bits in
+an MPI and to set or clear them:
+
+ -- Function: unsigned int gcry_mpi_get_nbits (gcry_mpi_t A)
+
+ Return the number of bits required to represent A.
+
+ -- Function: int gcry_mpi_test_bit (gcry_mpi_t A, unsigned int N)
+
+ Return true if bit number N (counting from 0) is set in A.
+
+ -- Function: void gcry_mpi_set_bit (gcry_mpi_t A, unsigned int N)
+
+ Set bit number N in A.
+
+ -- Function: void gcry_mpi_clear_bit (gcry_mpi_t A, unsigned int N)
+
+ Clear bit number N in A.
+
+ -- Function: void gcry_mpi_set_highbit (gcry_mpi_t A, unsigned int N)
+
+ Set bit number N in A and clear all bits greater than N.
+
+ -- Function: void gcry_mpi_clear_highbit (gcry_mpi_t A, unsigned int N)
+
+ Clear bit number N in A and all bits greater than N.
+
+ -- Function: void gcry_mpi_rshift (gcry_mpi_t X, gcry_mpi_t A,
+ unsigned int N)
+
+ Shift the value of A by N bits to the right and store the result in
+ X.
+
+ -- Function: void gcry_mpi_lshift (gcry_mpi_t X, gcry_mpi_t A,
+ unsigned int N)
+
+ Shift the value of A by N bits to the left and store the result in
+ X.
+
+\1f
+File: gcrypt.info, Node: EC functions, Next: Miscellaneous, Prev: Bit manipulations, Up: MPI library
+
+12.7 EC functions
+=================
+
+Libgcrypt provides an API to access low level functions used by its
+elliptic curve implementation. These functions allow to implement
+elliptic curve methods for which no explicit support is available.
+
+ -- Function: gcry_mpi_point_t gcry_mpi_point_new (unsigned int NBITS)
+
+ Allocate a new point object, initialize it to 0, and allocate
+ enough memory for a points of at least NBITS. This pre-allocation
+ yields only a small performance win and is not really necessary
+ because Libgcrypt automatically re-allocates the required memory.
+ Using 0 for NBITS is usually the right thing to do.
+
+ -- Function: void gcry_mpi_point_release (gcry_mpi_point_t POINT)
+
+ Release POINT and free all associated resources. Passing 'NULL' is
+ allowed and ignored.
+
+ -- Function: gcry_mpi_point_t gcry_mpi_point_copy
+ (gcry_mpi_point_t POINT)
+
+ Allocate and return a new point object and initialize it with
+ POINT. If POINT is NULL the function is identical to
+ 'gcry_mpi_point_new(0)'.
+
+ -- Function: void gcry_mpi_point_get (gcry_mpi_t X, gcry_mpi_t Y,
+ gcry_mpi_t Z, gcry_mpi_point_t POINT)
+
+ Store the projective coordinates from POINT into the MPIs X, Y, and
+ Z. If a coordinate is not required, 'NULL' may be used for X, Y,
+ or Z.
+
+ -- Function: void gcry_mpi_point_snatch_get (gcry_mpi_t X,
+ gcry_mpi_t Y, gcry_mpi_t Z, gcry_mpi_point_t POINT)
+
+ Store the projective coordinates from POINT into the MPIs X, Y, and
+ Z. If a coordinate is not required, 'NULL' may be used for X, Y,
+ or Z. The object POINT is then released. Using this function
+ instead of 'gcry_mpi_point_get' and 'gcry_mpi_point_release' has
+ the advantage of avoiding some extra memory allocations and copies.
+
+ -- Function: gcry_mpi_point_t gcry_mpi_point_set (
+ gcry_mpi_point_t POINT, gcry_mpi_t X, gcry_mpi_t Y,
+ gcry_mpi_t Z)
+
+ Store the projective coordinates from X, Y, and Z into POINT. If a
+ coordinate is given as 'NULL', the value 0 is used. If 'NULL' is
+ used for POINT a new point object is allocated and returned.
+ Returns POINT or the newly allocated point object.
+
+ -- Function: gcry_mpi_point_t gcry_mpi_point_snatch_set (
+ gcry_mpi_point_t POINT, gcry_mpi_t X, gcry_mpi_t Y,
+ gcry_mpi_t Z)
+
+ Store the projective coordinates from X, Y, and Z into POINT. If a
+ coordinate is given as 'NULL', the value 0 is used. If 'NULL' is
+ used for POINT a new point object is allocated and returned. The
+ MPIs X, Y, and Z are released. Using this function instead of
+ 'gcry_mpi_point_set' and 3 calls to 'gcry_mpi_release' has the
+ advantage of avoiding some extra memory allocations and copies.
+ Returns POINT or the newly allocated point object.
+
+ -- Function: gpg_error_t gcry_mpi_ec_new (gcry_ctx_t *R_CTX,
+ gcry_sexp_t KEYPARAM, const char *CURVENAME)
+
+ Allocate a new context for elliptic curve operations. If KEYPARAM
+ is given it specifies the parameters of the curve (*note
+ ecc_keyparam::). If CURVENAME is given in addition to KEYPARAM and
+ the key parameters do not include a named curve reference, the
+ string CURVENAME is used to fill in missing parameters. If only
+ CURVENAME is given, the context is initialized for this named
+ curve.
+
+ If a parameter specifying a point (e.g. 'g' or 'q') is not found,
+ the parser looks for a non-encoded point by appending '.x', '.y',
+ and '.z' to the parameter name and looking them all up to create a
+ point. A parameter with the suffix '.z' is optional and defaults
+ to 1.
+
+ On success the function returns 0 and stores the new context object
+ at R_CTX; this object eventually needs to be released (*note
+ gcry_ctx_release::). On error the function stores 'NULL' at R_CTX
+ and returns an error code.
+
+ -- Function: gcry_mpi_t gcry_mpi_ec_get_mpi ( const char *NAME,
+ gcry_ctx_t CTX, int COPY)
+
+ Return the MPI with NAME from the context CTX. If not found 'NULL'
+ is returned. If the returned MPI may later be modified, it is
+ suggested to pass '1' to COPY, so that the function guarantees that
+ a modifiable copy of the MPI is returned. If '0' is used for COPY,
+ this function may return a constant flagged MPI. In any case
+ 'gcry_mpi_release' needs to be called to release the result. For
+ valid names *note ecc_keyparam::. If the public key 'q' is
+ requested but only the private key 'd' is available, 'q' will be
+ recomputed on the fly. If a point parameter is requested it is
+ returned as an uncompressed encoded point unless these special
+ names are used:
+ Q@EDDSA
+ Return an EdDSA style compressed point. This is only
+ supported for Twisted Edwards curves.
+
+ -- Function: gcry_mpi_point_t gcry_mpi_ec_get_point ( const char *NAME,
+ gcry_ctx_t CTX, int COPY)
+
+ Return the point with NAME from the context CTX. If not found
+ 'NULL' is returned. If the returned MPI may later be modified, it
+ is suggested to pass '1' to COPY, so that the function guarantees
+ that a modifiable copy of the MPI is returned. If '0' is used for
+ COPY, this function may return a constant flagged point. In any
+ case 'gcry_mpi_point_release' needs to be called to release the
+ result. If the public key 'q' is requested but only the private
+ key 'd' is available, 'q' will be recomputed on the fly.
+
+ -- Function: gpg_error_t gcry_mpi_ec_set_mpi ( const char *NAME,
+ gcry_mpi_t NEWVALUE, gcry_ctx_t CTX)
+
+ Store the MPI NEWVALUE at NAME into the context CTX. On success
+ '0' is returned; on error an error code. Valid names are the MPI
+ parameters of an elliptic curve (*note ecc_keyparam::).
+
+ -- Function: gpg_error_t gcry_mpi_ec_set_point ( const char *NAME,
+ gcry_mpi_point_t NEWVALUE, gcry_ctx_t CTX)
+
+ Store the point NEWVALUE at NAME into the context CTX. On success
+ '0' is returned; on error an error code. Valid names are the point
+ parameters of an elliptic curve (*note ecc_keyparam::).
+
+ -- Function: gpg_err_code_t gcry_mpi_ec_decode_point (
+ mpi_point_t RESULT, gcry_mpi_t VALUE, gcry_ctx_t CTX)
+
+ Decode the point given as an MPI in VALUE and store at RESULT. To
+ decide which encoding is used the function takes a context CTX
+ which can be created with 'gcry_mpi_ec_new'. If 'NULL' is given
+ for the context the function assumes a 0x04 prefixed uncompressed
+ encoding. On error an error code is returned and RESULT might be
+ changed.
+
+ -- Function: int gcry_mpi_ec_get_affine ( gcry_mpi_t X, gcry_mpi_t Y,
+ gcry_mpi_point_t POINT, gcry_ctx_t CTX)
+
+ Compute the affine coordinates from the projective coordinates in
+ POINT and store them into X and Y. If one coordinate is not
+ required, 'NULL' may be passed to X or Y. CTX is the context
+ object which has been created using 'gcry_mpi_ec_new'. Returns 0
+ on success or not 0 if POINT is at infinity.
+
+ Note that you can use 'gcry_mpi_ec_set_point' with the value
+ 'GCRYMPI_CONST_ONE' for Z to convert affine coordinates back into
+ projective coordinates.
+
+ -- Function: void gcry_mpi_ec_dup ( gcry_mpi_point_t W,
+ gcry_mpi_point_t U, gcry_ctx_t CTX)
+
+ Double the point U of the elliptic curve described by CTX and store
+ the result into W.
+
+ -- Function: void gcry_mpi_ec_add ( gcry_mpi_point_t W,
+ gcry_mpi_point_t U, gcry_mpi_point_t V, gcry_ctx_t CTX)
+
+ Add the points U and V of the elliptic curve described by CTX and
+ store the result into W.
+
+ -- Function: void gcry_mpi_ec_sub ( gcry_mpi_point_t W,
+ gcry_mpi_point_t U, gcry_mpi_point_t V, gcry_ctx_t CTX)
+
+ Subtracts the point V from the point U of the elliptic curve
+ described by CTX and store the result into W. Only Twisted Edwards
+ curves are supported for now.
+
+ -- Function: void gcry_mpi_ec_mul ( gcry_mpi_point_t W, gcry_mpi_t N,
+ gcry_mpi_point_t U, gcry_ctx_t CTX)
+
+ Multiply the point U of the elliptic curve described by CTX by N
+ and store the result into W.
+
+ -- Function: int gcry_mpi_ec_curve_point ( gcry_mpi_point_t POINT,
+ gcry_ctx_t CTX)
+
+ Return true if POINT is on the elliptic curve described by CTX.
+
+\1f
+File: gcrypt.info, Node: Miscellaneous, Prev: EC functions, Up: MPI library
+
+12.8 Miscellaneous
+==================
+
+An MPI data type is allowed to be "misused" to store an arbitrary value.
+Two functions implement this kludge:
+
+ -- Function: gcry_mpi_t gcry_mpi_set_opaque (gcry_mpi_t A, void *P,
+ unsigned int NBITS)
+
+ Store NBITS of the value P points to in A and mark A as an opaque
+ value (i.e. an value that can't be used for any math calculation
+ and is only used to store an arbitrary bit pattern in A).
+ Ownership of P is taken by this function and thus the user may not
+ use dereference the passed value anymore. It is required that them
+ memory referenced by P has been allocated in a way that 'gcry_free'
+ is able to release it.
+
+ WARNING: Never use an opaque MPI for actual math operations. The
+ only valid functions are gcry_mpi_get_opaque and gcry_mpi_release.
+ Use gcry_mpi_scan to convert a string of arbitrary bytes into an
+ MPI.
+
+ -- Function: gcry_mpi_t gcry_mpi_set_opaque_copy (gcry_mpi_t A,
+ const void *P, unsigned int NBITS)
+
+ Same as 'gcry_mpi_set_opaque' but ownership of P is not taken
+ instead a copy of P is used.
+
+ -- Function: void * gcry_mpi_get_opaque (gcry_mpi_t A,
+ unsigned int *NBITS)
+
+ Return a pointer to an opaque value stored in A and return its size
+ in NBITS. Note that the returned pointer is still owned by A and
+ that the function should never be used for an non-opaque MPI.
+
+ Each MPI has an associated set of flags for special purposes. The
+currently defined flags are:
+
+'GCRYMPI_FLAG_SECURE'
+ Setting this flag converts A into an MPI stored in "secure memory".
+ Clearing this flag is not allowed.
+'GCRYMPI_FLAG_OPAQUE'
+ This is an interanl flag, indicating the an opaque valuue and not
+ an integer is stored. This is an read-only flag; it may not be set
+ or cleared.
+'GCRYMPI_FLAG_IMMUTABLE'
+ If this flag is set, the MPI is marked as immutable. Setting or
+ changing the value of that MPI is ignored and an error message is
+ logged. The flag is sometimes useful for debugging.
+'GCRYMPI_FLAG_CONST'
+ If this flag is set, the MPI is marked as a constant and as
+ immutable Setting or changing the value of that MPI is ignored and
+ an error message is logged. Such an MPI will never be deallocated
+ and may thus be used without copying. Note that using
+ gcry_mpi_copy will return a copy of that constant with this and the
+ immutable flag cleared. A few commonly used constants are
+ pre-defined and accessible using the macros 'GCRYMPI_CONST_ONE',
+ 'GCRYMPI_CONST_TWO', 'GCRYMPI_CONST_THREE', 'GCRYMPI_CONST_FOUR',
+ and 'GCRYMPI_CONST_EIGHT'.
+'GCRYMPI_FLAG_USER1'
+'GCRYMPI_FLAG_USER2'
+'GCRYMPI_FLAG_USER3'
+'GCRYMPI_FLAG_USER4'
+ These flags are reserved for use by the application.
+
+ -- Function: void gcry_mpi_set_flag (gcry_mpi_t A,
+ enum gcry_mpi_flag FLAG)
+
+ Set the FLAG for the MPI A. The only allowed flags are
+ 'GCRYMPI_FLAG_SECURE', 'GCRYMPI_FLAG_IMMUTABLE', and
+ 'GCRYMPI_FLAG_CONST'.
+
+ -- Function: void gcry_mpi_clear_flag (gcry_mpi_t A,
+ enum gcry_mpi_flag FLAG)
+
+ Clear FLAG for the multi-precision-integers A. The only allowed
+ flag is 'GCRYMPI_FLAG_IMMUTABLE' but only if 'GCRYMPI_FLAG_CONST'
+ is not set. If 'GCRYMPI_FLAG_CONST' is set, clearing
+ 'GCRYMPI_FLAG_IMMUTABLE' will simply be ignored.
+ o
+ -- Function: int gcry_mpi_get_flag (gcry_mpi_t A,
+ enum gcry_mpi_flag FLAG)
+
+ Return true if FLAG is set for A.
+
+ To put a random value into an MPI, the following convenience function
+may be used:
+
+ -- Function: void gcry_mpi_randomize (gcry_mpi_t W, unsigned int NBITS,
+ enum gcry_random_level LEVEL)
+
+ Set the multi-precision-integers W to a random non-negative number
+ of NBITS, using random data quality of level LEVEL. In case NBITS
+ is not a multiple of a byte, NBITS is rounded up to the next byte
+ boundary. When using a LEVEL of 'GCRY_WEAK_RANDOM' this function
+ makes use of 'gcry_create_nonce'.
+
+\1f
+File: gcrypt.info, Node: Prime numbers, Next: Utilities, Prev: MPI library, Up: Top
+
+13 Prime numbers
+****************
+
+* Menu:
+
+* Generation:: Generation of new prime numbers.
+* Checking:: Checking if a given number is prime.
+
+\1f
+File: gcrypt.info, Node: Generation, Next: Checking, Up: Prime numbers
+
+13.1 Generation
+===============
+
+ -- Function: gcry_error_t gcry_prime_generate (gcry_mpi_t
+ *PRIME,unsigned int PRIME_BITS, unsigned int FACTOR_BITS,
+ gcry_mpi_t **FACTORS, gcry_prime_check_func_t CB_FUNC, void
+ *CB_ARG, gcry_random_level_t RANDOM_LEVEL, unsigned int FLAGS)
+
+ Generate a new prime number of PRIME_BITS bits and store it in
+ PRIME. If FACTOR_BITS is non-zero, one of the prime factors of
+ (PRIME - 1) / 2 must be FACTOR_BITS bits long. If FACTORS is
+ non-zero, allocate a new, 'NULL'-terminated array holding the prime
+ factors and store it in FACTORS. FLAGS might be used to influence
+ the prime number generation process.
+
+ -- Function: gcry_error_t gcry_prime_group_generator (gcry_mpi_t *R_G,
+ gcry_mpi_t PRIME, gcry_mpi_t *FACTORS, gcry_mpi_t START_G)
+
+ Find a generator for PRIME where the factorization of (PRIME-1) is
+ in the 'NULL' terminated array FACTORS. Return the generator as a
+ newly allocated MPI in R_G. If START_G is not NULL, use this as
+ the start for the search.
+
+ -- Function: void gcry_prime_release_factors (gcry_mpi_t *FACTORS)
+
+ Convenience function to release the FACTORS array.
+
+\1f
+File: gcrypt.info, Node: Checking, Prev: Generation, Up: Prime numbers
+
+13.2 Checking
+=============
+
+ -- Function: gcry_error_t gcry_prime_check (gcry_mpi_t P, unsigned int
+ FLAGS)
+
+ Check whether the number P is prime. Returns zero in case P is
+ indeed a prime, returns 'GPG_ERR_NO_PRIME' in case P is not a prime
+ and a different error code in case something went horribly wrong.
+
+\1f
+File: gcrypt.info, Node: Utilities, Next: Tools, Prev: Prime numbers, Up: Top
+
+14 Utilities
+************
+
+* Menu:
+
+* Memory allocation:: Functions related with memory allocation.
+* Context management:: Functions related with context management.
+* Buffer description:: A data type to describe buffers.
+* Config reporting:: How to return Libgcrypt's configuration.
+
+\1f
+File: gcrypt.info, Node: Memory allocation, Next: Context management, Up: Utilities
+
+14.1 Memory allocation
+======================
+
+ -- Function: void * gcry_malloc (size_t N)
+
+ This function tries to allocate N bytes of memory. On success it
+ returns a pointer to the memory area, in an out-of-core condition,
+ it returns NULL.
+
+ -- Function: void * gcry_malloc_secure (size_t N)
+ Like 'gcry_malloc', but uses secure memory.
+
+ -- Function: void * gcry_calloc (size_t N, size_t M)
+
+ This function allocates a cleared block of memory (i.e.
+ initialized with zero bytes) long enough to contain a vector of N
+ elements, each of size M bytes. On success it returns a pointer to
+ the memory block; in an out-of-core condition, it returns NULL.
+
+ -- Function: void * gcry_calloc_secure (size_t N, size_t M)
+ Like 'gcry_calloc', but uses secure memory.
+
+ -- Function: void * gcry_realloc (void *P, size_t N)
+
+ This function tries to resize the memory area pointed to by P to N
+ bytes. On success it returns a pointer to the new memory area, in
+ an out-of-core condition, it returns NULL. Depending on whether the
+ memory pointed to by P is secure memory or not, gcry_realloc tries
+ to use secure memory as well.
+
+ -- Function: void gcry_free (void *P)
+ Release the memory area pointed to by P.
+
+\1f
+File: gcrypt.info, Node: Context management, Next: Buffer description, Prev: Memory allocation, Up: Utilities
+
+14.2 Context management
+=======================
+
+Some function make use of a context object. As of now there are only a
+few math functions. However, future versions of Libgcrypt may make more
+use of this context object.
+
+ -- Data type: gcry_ctx_t
+ This type is used to refer to the general purpose context object.
+
+ -- Function: void gcry_ctx_release (gcry_ctx_t CTX)
+ Release the context object CTX and all associated resources. A
+ 'NULL' passed as CTX is ignored.
+
+\1f
+File: gcrypt.info, Node: Buffer description, Next: Config reporting, Prev: Context management, Up: Utilities
+
+14.3 Buffer description
+=======================
+
+To help hashing non-contiguous areas of memory a general purpose data
+type is defined:
+
+ -- Data type: gcry_buffer_t
+ This type is a structure to describe a buffer. The user should
+ make sure that this structure is initialized to zero. The
+ available fields of this structure are:
+
+ '.size'
+ This is either 0 for no information available or indicates the
+ allocated length of the buffer.
+ '.off'
+ This is the offset into the buffer.
+ '.len'
+ This is the valid length of the buffer starting at '.off'.
+ '.data'
+ This is the address of the buffer.
+
+\1f
+File: gcrypt.info, Node: Config reporting, Prev: Buffer description, Up: Utilities
+
+14.4 How to return Libgcrypt's configuration.
+=============================================
+
+Although 'GCRYCTL_PRINT_CONFIG' can be used to print configuration
+options, it is sometimes necessary to check them in a program. This can
+be accomplished by using this function:
+
+ -- Function: char * gcry_get_config (int MODE, const char *WHAT)
+
+ This function returns a malloced string with colon delimited
+ configure options. With a value of 0 for MODE this string
+ resembles the output of 'GCRYCTL_PRINT_CONFIG'. However, if WHAT
+ is not NULL, only the line where the first field (e.g. "cpu-arch")
+ matches WHAT is returned.
+
+ Other values than 0 for MODE are not defined. The caller shall
+ free the string using 'gcry_free'. On error NULL is returned and
+ ERRNO is set; if a value for WHAT is unknow ERRNO will be set to 0.
+
+\1f
+File: gcrypt.info, Node: Tools, Next: Configuration, Prev: Utilities, Up: Top
+
+15 Tools
+********
+
+* Menu:
+
+* hmac256:: A standalone HMAC-SHA-256 implementation
+
+\1f
+File: gcrypt.info, Node: hmac256, Up: Tools
+
+15.1 A HMAC-SHA-256 tool
+========================
+
+This is a standalone HMAC-SHA-256 implementation used to compute an
+HMAC-SHA-256 message authentication code. The tool has originally been
+developed as a second implementation for Libgcrypt to allow comparing
+against the primary implementation and to be used for internal
+consistency checks. It should not be used for sensitive data because no
+mechanisms to clear the stack etc are used.
+
+ The code has been written in a highly portable manner and requires
+only a few standard definitions to be provided in a config.h file.
+
+'hmac256' is commonly invoked as
+
+ hmac256 "This is my key" foo.txt
+
+This compute the MAC on the file 'foo.txt' using the key given on the
+command line.
+
+'hmac256' understands these options:
+
+'--binary'
+ Print the MAC as a binary string. The default is to print the MAC
+ encoded has lower case hex digits.
+
+'--version'
+ Print version of the program and exit.
+
+\1f
+File: gcrypt.info, Node: Configuration, Next: Architecture, Prev: Tools, Up: Top
+
+16 Configuration files and environment variables
+************************************************
+
+This chapter describes which files and environment variables can be used
+to change the behaviour of Libgcrypt.
+
+The environment variables considered by Libgcrypt are:
+
+'GCRYPT_BARRETT'
+ By setting this variable to any value a different algorithm for
+ modular reduction is used for ECC.
+
+'GCRYPT_RNDUNIX_DBG'
+'GCRYPT_RNDUNIX_DBGALL'
+ These two environment variables are used to enable debug output for
+ the rndunix entropy gatherer, which is used on systems lacking a
+ /dev/random device. The value of 'GCRYPT_RNDUNIX_DBG' is a file
+ name or '-' for stdout. Debug output is the written to this file.
+ By setting 'GCRYPT_RNDUNIX_DBGALL' to any value the debug output
+ will be more verbose.
+
+'GCRYPT_RNDW32_NOPERF'
+ Setting this environment variable on Windows to any value disables
+ the use of performance data ('HKEY_PERFORMANCE_DATA') as source for
+ entropy. On some older Windows systems this could help to speed up
+ the creation of random numbers but also decreases the amount of
+ data used to init the random number generator.
+
+'GCRYPT_RNDW32_DBG'
+ Setting the value of this variable to a positive integer logs
+ information about the Windows entropy gatherer using the standard
+ log interface.
+
+'HOME'
+ This is used to locate the socket to connect to the EGD random
+ daemon. The EGD can be used on system without a /dev/random to
+ speed up the random number generator. It is not needed on the
+ majority of today's operating systems and support for EGD requires
+ the use of a configure option at build time.
+
+The files which Libgcrypt uses to retrieve system information and the
+files which can be created by the user to modify Libgcrypt's behavior
+are:
+
+'/etc/gcrypt/hwf.deny'
+ This file can be used to disable the use of hardware based
+ optimizations, *note hardware features::.
+
+'/etc/gcrypt/random.conf'
+ This file can be used to globally change parameters of the random
+ generator. The file is a simple text file where empty lines and
+ lines with the first non white-space character being '#' are
+ ignored. Supported options are
+
+ 'disable-jent'
+ Disable the use of the jitter based entropy generator.
+
+ 'only-urandom'
+ Always use the non-blocking /dev/urandom or the respective
+ system call instead of the blocking /dev/random. If Libgcrypt
+ is used early in the boot process of the system, this option
+ should only be used if the system also supports the getrandom
+ system call.
+
+'/etc/gcrypt/fips_enabled'
+'/proc/sys/crypto/fips_enabled'
+ On Linux these files are used to enable FIPS mode, *note enabling
+ fips mode::.
+
+'/proc/cpuinfo'
+'/proc/self/auxv'
+ On Linux running on the ARM architecture, these files are used to
+ read hardware capabilities of the CPU.
+
+\1f
+File: gcrypt.info, Node: Architecture, Next: Self-Tests, Prev: Configuration, Up: Top
+
+17 Architecture
+***************
+
+This chapter describes the internal architecture of Libgcrypt.
+
+ Libgcrypt is a function library written in ISO C-90. Any compliant
+compiler should be able to build Libgcrypt as long as the target is
+either a POSIX platform or compatible to the API used by Windows NT.
+Provisions have been take so that the library can be directly used from
+C++ applications; however building with a C++ compiler is not supported.
+
+ Building Libgcrypt is done by using the common './configure && make'
+approach. The configure command is included in the source distribution
+and as a portable shell script it works on any Unix-alike system. The
+result of running the configure script are a C header file ('config.h'),
+customized Makefiles, the setup of symbolic links and a few other
+things. After that the make tool builds and optionally installs the
+library and the documentation. See the files 'INSTALL' and 'README' in
+the source distribution on how to do this.
+
+ Libgcrypt is developed using a Subversion(1) repository. Although
+all released versions are tagged in this repository, they should not be
+used to build production versions of Libgcrypt. Instead released
+tarballs should be used. These tarballs are available from several
+places with the master copy at 'ftp://ftp.gnupg.org/gcrypt/libgcrypt/'.
+Announcements of new releases are posted to the
+'gnupg-announce@gnupg.org' mailing list(2).
+
+ \0\b[image src="libgcrypt-modules.png" alt="Libgcrypt subsystems"\0\b]
+
+Figure 17.1: Libgcrypt subsystems
+
+ Libgcrypt consists of several subsystems (*note Figure 17.1:
+fig:subsystems.) and all these subsystems provide a public API; this
+includes the helper subsystems like the one for S-expressions. The API
+style depends on the subsystem; in general an open-use-close approach is
+implemented. The open returns a handle to a context used for all
+further operations on this handle, several functions may then be used on
+this handle and a final close function releases all resources associated
+with the handle.
+
+* Menu:
+
+* Public-Key Subsystem Architecture:: About public keys.
+* Symmetric Encryption Subsystem Architecture:: About standard ciphers.
+* Hashing and MACing Subsystem Architecture:: About hashing.
+* Multi-Precision-Integer Subsystem Architecture:: About big integers.
+* Prime-Number-Generator Subsystem Architecture:: About prime numbers.
+* Random-Number Subsystem Architecture:: About random stuff.
+
+ ---------- Footnotes ----------
+
+ (1) A version control system available for many platforms
+
+ (2) See <http://www.gnupg.org/documentation/mailing-lists.en.html>
+for details.
+
+\1f
+File: gcrypt.info, Node: Public-Key Subsystem Architecture, Next: Symmetric Encryption Subsystem Architecture, Up: Architecture
+
+17.1 Public-Key Architecture
+============================
+
+Because public key cryptography is almost always used to process small
+amounts of data (hash values or session keys), the interface is not
+implemented using the open-use-close paradigm, but with single
+self-contained functions. Due to the wide variety of parameters
+required by different algorithms S-expressions, as flexible way to
+convey these parameters, are used. There is a set of helper functions
+to work with these S-expressions.
+
+ Aside of functions to register new algorithms, map algorithms names
+to algorithms identifiers and to lookup properties of a key, the
+following main functions are available:
+
+'gcry_pk_encrypt'
+ Encrypt data using a public key.
+
+'gcry_pk_decrypt'
+ Decrypt data using a private key.
+
+'gcry_pk_sign'
+ Sign data using a private key.
+
+'gcry_pk_verify'
+ Verify that a signature matches the data.
+
+'gcry_pk_testkey'
+ Perform a consistency over a public or private key.
+
+'gcry_pk_genkey'
+ Create a new public/private key pair.
+
+ All these functions lookup the module implementing the algorithm and
+pass the actual work to that module. The parsing of the S-expression
+input and the construction of S-expression for the return values is done
+by the high level code ('cipher/pubkey.c'). Thus the internal interface
+between the algorithm modules and the high level functions passes data
+in a custom format.
+
+ By default Libgcrypt uses a blinding technique for RSA decryption to
+mitigate real world timing attacks over a network: Instead of using the
+RSA decryption directly, a blinded value y = x r^{e} \bmod n is
+decrypted and the unblinded value x' = y' r^{-1} \bmod n returned. The
+blinding value r is a random value with the size of the modulus n and
+generated with 'GCRY_WEAK_RANDOM' random level.
+
+ The algorithm used for RSA and DSA key generation depends on whether
+Libgcrypt is operated in standard or in FIPS mode. In standard mode an
+algorithm based on the Lim-Lee prime number generator is used. In FIPS
+mode RSA keys are generated as specified in ANSI X9.31 (1998) and DSA
+keys as specified in FIPS 186-2.
+
+\1f
+File: gcrypt.info, Node: Symmetric Encryption Subsystem Architecture, Next: Hashing and MACing Subsystem Architecture, Prev: Public-Key Subsystem Architecture, Up: Architecture
+
+17.2 Symmetric Encryption Subsystem Architecture
+================================================
+
+The interface to work with symmetric encryption algorithms is made up of
+functions from the 'gcry_cipher_' name space. The implementation
+follows the open-use-close paradigm and uses registered algorithm
+modules for the actual work. Unless a module implements optimized
+cipher mode implementations, the high level code ('cipher/cipher.c')
+implements the modes and calls the core algorithm functions to process
+each block.
+
+ The most important functions are:
+
+'gcry_cipher_open'
+ Create a new instance to encrypt or decrypt using a specified
+ algorithm and mode.
+
+'gcry_cipher_close'
+ Release an instance.
+
+'gcry_cipher_setkey'
+ Set a key to be used for encryption or decryption.
+
+'gcry_cipher_setiv'
+ Set an initialization vector to be used for encryption or
+ decryption.
+
+'gcry_cipher_encrypt'
+'gcry_cipher_decrypt'
+ Encrypt or decrypt data. These functions may be called with
+ arbitrary amounts of data and as often as needed to encrypt or
+ decrypt all data.
+
+ There are also functions to query properties of algorithms or
+context, like block length, key length, map names or to enable features
+like padding methods.
+
+\1f
+File: gcrypt.info, Node: Hashing and MACing Subsystem Architecture, Next: Multi-Precision-Integer Subsystem Architecture, Prev: Symmetric Encryption Subsystem Architecture, Up: Architecture
+
+17.3 Hashing and MACing Subsystem Architecture
+==============================================
+
+The interface to work with message digests and CRC algorithms is made up
+of functions from the 'gcry_md_' name space. The implementation follows
+the open-use-close paradigm and uses registered algorithm modules for
+the actual work. Although CRC algorithms are not considered
+cryptographic hash algorithms, they share enough properties so that it
+makes sense to handle them in the same way. It is possible to use
+several algorithms at once with one context and thus compute them all on
+the same data.
+
+ The most important functions are:
+
+'gcry_md_open'
+ Create a new message digest instance and optionally enable one
+ algorithm. A flag may be used to turn the message digest algorithm
+ into a HMAC algorithm.
+
+'gcry_md_enable'
+ Enable an additional algorithm for the instance.
+
+'gcry_md_setkey'
+ Set the key for the MAC.
+
+'gcry_md_write'
+ Pass more data for computing the message digest to an instance.
+
+'gcry_md_putc'
+ Buffered version of 'gcry_md_write' implemented as a macro.
+
+'gcry_md_read'
+ Finalize the computation of the message digest or HMAC and return
+ the result.
+
+'gcry_md_close'
+ Release an instance
+
+'gcry_md_hash_buffer'
+ Convenience function to directly compute a message digest over a
+ memory buffer without the need to create an instance first.
+
+ There are also functions to query properties of algorithms or the
+instance, like enabled algorithms, digest length, map algorithm names.
+it is also possible to reset an instance or to copy the current state of
+an instance at any time. Debug functions to write the hashed data to
+files are available as well.
+
+\1f
+File: gcrypt.info, Node: Multi-Precision-Integer Subsystem Architecture, Next: Prime-Number-Generator Subsystem Architecture, Prev: Hashing and MACing Subsystem Architecture, Up: Architecture
+
+17.4 Multi-Precision-Integer Subsystem Architecture
+===================================================
+
+The implementation of Libgcrypt's big integer computation code is based
+on an old release of GNU Multi-Precision Library (GMP). The decision not
+to use the GMP library directly was due to stalled development at that
+time and due to security requirements which could not be provided by the
+code in GMP. As GMP does, Libgcrypt provides high performance assembler
+implementations of low level code for several CPUS to gain much better
+performance than with a generic C implementation.
+
+Major features of Libgcrypt's multi-precision-integer code compared to
+GMP are:
+
+ * Avoidance of stack based allocations to allow protection against
+ swapping out of sensitive data and for easy zeroing of sensitive
+ intermediate results.
+
+ * Optional use of secure memory and tracking of its use so that
+ results are also put into secure memory.
+
+ * MPIs are identified by a handle (implemented as a pointer) to give
+ better control over allocations and to augment them with extra
+ properties like opaque data.
+
+ * Removal of unnecessary code to reduce complexity.
+
+ * Functions specialized for public key cryptography.
+
+\1f
+File: gcrypt.info, Node: Prime-Number-Generator Subsystem Architecture, Next: Random-Number Subsystem Architecture, Prev: Multi-Precision-Integer Subsystem Architecture, Up: Architecture
+
+17.5 Prime-Number-Generator Subsystem Architecture
+==================================================
+
+Libgcrypt provides an interface to its prime number generator. These
+functions make use of the internal prime number generator which is
+required for the generation for public key key pairs. The plain prime
+checking function is exported as well.
+
+ The generation of random prime numbers is based on the Lim and Lee
+algorithm to create practically save primes.(1) This algorithm creates
+a pool of smaller primes, select a few of them to create candidate
+primes of the form 2 * p_0 * p_1 * ... * p_n + 1, tests the candidate
+for primality and permutates the pool until a prime has been found. It
+is possible to clamp one of the small primes to a certain size to help
+DSA style algorithms. Because most of the small primes in the pool are
+not used for the resulting prime number, they are saved for later use
+(see 'save_pool_prime' and 'get_pool_prime' in 'cipher/primegen.c').
+The prime generator optionally supports the finding of an appropriate
+generator.
+
+The primality test works in three steps:
+
+ 1. The standard sieve algorithm using the primes up to 4999 is used as
+ a quick first check.
+
+ 2. A Fermat test filters out almost all non-primes.
+
+ 3. A 5 round Rabin-Miller test is finally used. The first round uses
+ a witness of 2, whereas the next rounds use a random witness.
+
+ To support the generation of RSA and DSA keys in FIPS mode according
+to X9.31 and FIPS 186-2, Libgcrypt implements two additional prime
+generation functions: '_gcry_derive_x931_prime' and
+'_gcry_generate_fips186_2_prime'. These functions are internal and not
+available through the public API.
+
+ ---------- Footnotes ----------
+
+ (1) Chae Hoon Lim and Pil Joong Lee. A key recovery attack on
+discrete log-based schemes using a prime order subgroup. In Burton S.
+Kaliski Jr., editor, Advances in Cryptology: Crypto '97, pages 249-263,
+Berlin / Heidelberg / New York, 1997. Springer-Verlag. Described on
+page 260.
+
+\1f
+File: gcrypt.info, Node: Random-Number Subsystem Architecture, Prev: Prime-Number-Generator Subsystem Architecture, Up: Architecture
+
+17.6 Random-Number Subsystem Architecture
+=========================================
+
+Libgcrypt provides 3 levels or random quality: The level
+'GCRY_VERY_STRONG_RANDOM' usually used for key generation, the level
+'GCRY_STRONG_RANDOM' for all other strong random requirements and the
+function 'gcry_create_nonce' which is used for weaker usages like
+nonces. There is also a level 'GCRY_WEAK_RANDOM' which in general maps
+to 'GCRY_STRONG_RANDOM' except when used with the function
+'gcry_mpi_randomize', where it randomizes an multi-precision-integer
+using the 'gcry_create_nonce' function.
+
+There are two distinct random generators available:
+
+ * The Continuously Seeded Pseudo Random Number Generator (CSPRNG),
+ which is based on the classic GnuPG derived big pool
+ implementation. Implemented in 'random/random-csprng.c' and used
+ by default.
+ * A FIPS approved ANSI X9.31 PRNG using AES with a 128 bit key.
+ Implemented in 'random/random-fips.c' and used if Libgcrypt is in
+ FIPS mode.
+
+Both generators make use of so-called entropy gathering modules:
+
+rndlinux
+ Uses the operating system provided '/dev/random' and '/dev/urandom'
+ devices. The '/dev/gcrypt/random.conf' config option
+ 'only-urandom' can be used to inhibit the use of the blocking
+ '/dev/random' device.
+
+rndunix
+ Runs several operating system commands to collect entropy from
+ sources like virtual machine and process statistics. It is a kind
+ of poor-man's '/dev/random' implementation. It is not available in
+ FIPS mode.
+
+rndegd
+ Uses the operating system provided Entropy Gathering Daemon (EGD).
+ The EGD basically uses the same algorithms as rndunix does.
+ However as a system daemon it keeps on running and thus can serve
+ several processes requiring entropy input and does not waste
+ collected entropy if the application does not need all the
+ collected entropy. It is not available in FIPS mode.
+
+rndw32
+ Targeted for the Microsoft Windows OS. It uses certain properties
+ of that system and is the only gathering module available for that
+ OS.
+
+rndhw
+ Extra module to collect additional entropy by utilizing a hardware
+ random number generator. As of now the supported hardware RNG is
+ the Padlock engine of VIA (Centaur) CPUs and x86 CPUs with the
+ RDRAND instruction. It is not available in FIPS mode.
+
+rndjent
+ Extra module to collect additional entropy using a CPU jitter based
+ approach. This is only used on X86 hardware where the RDTSC opcode
+ is available. The '/dev/gcrypt/random.conf' config option
+ 'disable-jent' can be used to inhibit the use of this module.
+
+* Menu:
+
+* CSPRNG Description:: Description of the CSPRNG.
+* FIPS PRNG Description:: Description of the FIPS X9.31 PRNG.
+
+\1f
+File: gcrypt.info, Node: CSPRNG Description, Next: FIPS PRNG Description, Up: Random-Number Subsystem Architecture
+
+17.6.1 Description of the CSPRNG
+--------------------------------
+
+This random number generator is loosely modelled after the one described
+in Peter Gutmann's paper: "Software Generation of Practically Strong
+Random Numbers".(1)
+
+ A pool of 600 bytes is used and mixed using the core SHA-1 hash
+transform function. Several extra features are used to make the robust
+against a wide variety of attacks and to protect against failures of
+subsystems. The state of the generator may be saved to a file and
+initially seed form a file.
+
+ Depending on how Libgcrypt was build the generator is able to select
+the best working entropy gathering module. It makes use of the slow and
+fast collection methods and requires the pool to initially seeded form
+the slow gatherer or a seed file. An entropy estimation is used to mix
+in enough data from the gather modules before returning the actual
+random output. Process fork detection and protection is implemented.
+
+ The implementation of the nonce generator (for 'gcry_create_nonce')
+is a straightforward repeated hash design: A 28 byte buffer is initially
+seeded with the PID and the time in seconds in the first 20 bytes and
+with 8 bytes of random taken from the 'GCRY_STRONG_RANDOM' generator.
+Random numbers are then created by hashing all the 28 bytes with SHA-1
+and saving that again in the first 20 bytes. The hash is also returned
+as result.
+
+ ---------- Footnotes ----------
+
+ (1) Also described in chapter 6 of his book "Cryptographic Security
+Architecture", New York, 2004, ISBN 0-387-95387-6.
+
+\1f
+File: gcrypt.info, Node: FIPS PRNG Description, Prev: CSPRNG Description, Up: Random-Number Subsystem Architecture
+
+17.6.2 Description of the FIPS X9.31 PRNG
+-----------------------------------------
+
+The core of this deterministic random number generator is implemented
+according to the document "NIST-Recommended Random Number Generator
+Based on ANSI X9.31 Appendix A.2.4 Using the 3-Key Triple DES and AES
+Algorithms", dated 2005-01-31. This implementation uses the AES
+variant.
+
+ The generator is based on contexts to utilize the same core functions
+for all random levels as required by the high-level interface. All
+random generators return their data in 128 bit blocks. If the caller
+requests less bits, the extra bits are not used. The key for each
+generator is only set once at the first time a generator context is
+used. The seed value is set along with the key and again after 1000
+output blocks.
+
+ On Unix like systems the 'GCRY_VERY_STRONG_RANDOM' and
+'GCRY_STRONG_RANDOM' generators are keyed and seeded using the rndlinux
+module with the '/dev/random' device. Thus these generators may block
+until the OS kernel has collected enough entropy. When used with
+Microsoft Windows the rndw32 module is used instead.
+
+ The generator used for 'gcry_create_nonce' is keyed and seeded from
+the 'GCRY_STRONG_RANDOM' generator. Thus is may also block if the
+'GCRY_STRONG_RANDOM' generator has not yet been used before and thus
+gets initialized on the first use by 'gcry_create_nonce'. This special
+treatment is justified by the weaker requirements for a nonce generator
+and to save precious kernel entropy for use by the "real" random
+generators.
+
+ A self-test facility uses a separate context to check the
+functionality of the core X9.31 functions using a known answers test.
+During runtime each output block is compared to the previous one to
+detect a stuck generator.
+
+ The DT value for the generator is made up of the current time down to
+microseconds (if available) and a free running 64 bit counter. When
+used with the test context the DT value is taken from the context and
+incremented on each use.
+
+\1f
+File: gcrypt.info, Node: Self-Tests, Next: FIPS Mode, Prev: Architecture, Up: Top
+
+Appendix A Description of the Self-Tests
+****************************************
+
+In addition to the build time regression test suite, Libgcrypt
+implements self-tests to be performed at runtime. Which self-tests are
+actually used depends on the mode Libgcrypt is used in. In standard
+mode a limited set of self-tests is run at the time an algorithm is
+first used. Note that not all algorithms feature a self-test in
+standard mode. The 'GCRYCTL_SELFTEST' control command may be used to
+run all implemented self-tests at any time; this will even run more
+tests than those run in FIPS mode.
+
+ If any of the self-tests fails, the library immediately returns an
+error code to the caller. If Libgcrypt is in FIPS mode the self-tests
+will be performed within the "Self-Test" state and any failure puts the
+library into the "Error" state.
+
+A.1 Power-Up Tests
+==================
+
+Power-up tests are only performed if Libgcrypt is in FIPS mode.
+
+A.1.1 Symmetric Cipher Algorithm Power-Up Tests
+-----------------------------------------------
+
+The following symmetric encryption algorithm tests are run during
+power-up:
+
+3DES
+ To test the 3DES 3-key EDE encryption in ECB mode these tests are
+ run:
+ 1. A known answer test is run on a 64 bit test vector processed
+ by 64 rounds of Single-DES block encryption and decryption
+ using a key changed with each round.
+ 2. A known answer test is run on a 64 bit test vector processed
+ by 16 rounds of 2-key and 3-key Triple-DES block encryption
+ and decryptions using a key changed with each round.
+ 3. 10 known answer tests using 3-key Triple-DES EDE encryption,
+ comparing the ciphertext to the known value, then running a
+ decryption and comparing it to the initial plaintext.
+ ('cipher/des.c:selftest')
+
+AES-128
+ A known answer tests is run using one test vector and one test key
+ with AES in ECB mode. ('cipher/rijndael.c:selftest_basic_128')
+
+AES-192
+ A known answer tests is run using one test vector and one test key
+ with AES in ECB mode. ('cipher/rijndael.c:selftest_basic_192')
+
+AES-256
+ A known answer tests is run using one test vector and one test key
+ with AES in ECB mode. ('cipher/rijndael.c:selftest_basic_256')
+
+A.1.2 Hash Algorithm Power-Up Tests
+-----------------------------------
+
+The following hash algorithm tests are run during power-up:
+
+SHA-1
+ A known answer test using the string '"abc"' is run.
+ ('cipher/sha1.c:selftests_sha1')
+SHA-224
+ A known answer test using the string '"abc"' is run.
+ ('cipher/sha256.c:selftests_sha224')
+SHA-256
+ A known answer test using the string '"abc"' is run.
+ ('cipher/sha256.c:selftests_sha256')
+SHA-384
+ A known answer test using the string '"abc"' is run.
+ ('cipher/sha512.c:selftests_sha384')
+SHA-512
+ A known answer test using the string '"abc"' is run.
+ ('cipher/sha512.c:selftests_sha512')
+
+A.1.3 MAC Algorithm Power-Up Tests
+----------------------------------
+
+The following MAC algorithm tests are run during power-up:
+
+HMAC SHA-1
+ A known answer test using 9 byte of data and a 64 byte key is run.
+ ('cipher/hmac-tests.c:selftests_sha1')
+HMAC SHA-224
+ A known answer test using 28 byte of data and a 4 byte key is run.
+ ('cipher/hmac-tests.c:selftests_sha224')
+HMAC SHA-256
+ A known answer test using 28 byte of data and a 4 byte key is run.
+ ('cipher/hmac-tests.c:selftests_sha256')
+HMAC SHA-384
+ A known answer test using 28 byte of data and a 4 byte key is run.
+ ('cipher/hmac-tests.c:selftests_sha384')
+HMAC SHA-512
+ A known answer test using 28 byte of data and a 4 byte key is run.
+ ('cipher/hmac-tests.c:selftests_sha512')
+
+A.1.4 Random Number Power-Up Test
+---------------------------------
+
+The DRNG is tested during power-up this way:
+
+ 1. Requesting one block of random using the public interface to check
+ general working and the duplicated block detection.
+ 2. 3 know answer tests using pre-defined keys, seed and initial DT
+ values. For each test 3 blocks of 16 bytes are requested and
+ compared to the expected result. The DT value is incremented for
+ each block.
+
+A.1.5 Public Key Algorithm Power-Up Tests
+-----------------------------------------
+
+The public key algorithms are tested during power-up:
+
+RSA
+ A pre-defined 1024 bit RSA key is used and these tests are run in
+ turn:
+ 1. Conversion of S-expression to internal format.
+ ('cipher/rsa.c:selftests_rsa')
+ 2. Private key consistency check. ('cipher/rsa.c:selftests_rsa')
+ 3. A pre-defined 20 byte value is signed with PKCS#1 padding for
+ SHA-1. The result is verified using the public key against
+ the original data and against modified data.
+ ('cipher/rsa.c:selftest_sign_1024')
+ 4. A 1000 bit random value is encrypted and checked that it does
+ not match the original random value. The encrypted result is
+ then decrypted and checked that it matches the original random
+ value. ('cipher/rsa.c:selftest_encr_1024')
+
+DSA
+ A pre-defined 1024 bit DSA key is used and these tests are run in
+ turn:
+ 1. Conversion of S-expression to internal format.
+ ('cipher/dsa.c:selftests_dsa')
+ 2. Private key consistency check. ('cipher/dsa.c:selftests_dsa')
+ 3. A pre-defined 20 byte value is signed with PKCS#1 padding for
+ SHA-1. The result is verified using the public key against
+ the original data and against modified data.
+ ('cipher/dsa.c:selftest_sign_1024')
+
+A.1.6 Integrity Power-Up Tests
+------------------------------
+
+The integrity of the Libgcrypt is tested during power-up but only if
+checking has been enabled at build time. The check works by computing a
+HMAC SHA-256 checksum over the file used to load Libgcrypt into memory.
+That checksum is compared against a checksum stored in a file of the
+same name but with a single dot as a prefix and a suffix of '.hmac'.
+
+A.1.7 Critical Functions Power-Up Tests
+---------------------------------------
+
+The 3DES weak key detection is tested during power-up by calling the
+detection function with keys taken from a table listening all weak keys.
+The table itself is protected using a SHA-1 hash.
+('cipher/des.c:selftest')
+
+A.2 Conditional Tests
+=====================
+
+The conditional tests are performed if a certain condition is met. This
+may occur at any time; the library does not necessary enter the
+"Self-Test" state to run these tests but will transit to the "Error"
+state if a test failed.
+
+A.2.1 Key-Pair Generation Tests
+-------------------------------
+
+After an asymmetric key-pair has been generated, Libgcrypt runs a
+pair-wise consistency tests on the generated key. On failure the
+generated key is not used, an error code is returned and, if in FIPS
+mode, the library is put into the "Error" state.
+
+RSA
+ The test uses a random number 64 bits less the size of the modulus
+ as plaintext and runs an encryption and decryption operation in
+ turn. The encrypted value is checked to not match the plaintext
+ and the result of the decryption is checked to match the plaintext.
+
+ A new random number of the same size is generated, signed and
+ verified to test the correctness of the signing operation. As a
+ second signing test, the signature is modified by incrementing its
+ value and then verified with the expected result that the
+ verification fails. ('cipher/rsa.c:test_keys')
+DSA
+ The test uses a random number of the size of the Q parameter to
+ create a signature and then checks that the signature verifies. As
+ a second signing test, the data is modified by incrementing its
+ value and then verified against the signature with the expected
+ result that the verification fails. ('cipher/dsa.c:test_keys')
+
+A.2.2 Software Load Tests
+-------------------------
+
+No code is loaded at runtime.
+
+A.2.3 Manual Key Entry Tests
+----------------------------
+
+A manual key entry feature is not implemented in Libgcrypt.
+
+A.2.4 Continuous RNG Tests
+--------------------------
+
+The continuous random number test is only used in FIPS mode. The RNG
+generates blocks of 128 bit size; the first block generated per context
+is saved in the context and another block is generated to be returned to
+the caller. Each block is compared against the saved block and then
+stored in the context. If a duplicated block is detected an error is
+signaled and the library is put into the "Fatal-Error" state.
+('random/random-fips.c:x931_aes_driver')
+
+A.3 Application Requested Tests
+===============================
+
+The application may requests tests at any time by means of the
+'GCRYCTL_SELFTEST' control command. Note that using these tests is not
+FIPS conform: Although Libgcrypt rejects all application requests for
+services while running self-tests, it does not ensure that no other
+operations of Libgcrypt are still being executed. Thus, in FIPS mode an
+application requesting self-tests needs to power-cycle Libgcrypt
+instead.
+
+ When self-tests are requested, Libgcrypt runs all the tests it does
+during power-up as well as a few extra checks as described below.
+
+A.3.1 Symmetric Cipher Algorithm Tests
+--------------------------------------
+
+The following symmetric encryption algorithm tests are run in addition
+to the power-up tests:
+
+AES-128
+ A known answer tests with test vectors taken from NIST SP800-38a
+ and using the high level functions is run for block modes CFB and
+ OFB.
+
+A.3.2 Hash Algorithm Tests
+--------------------------
+
+The following hash algorithm tests are run in addition to the power-up
+tests:
+
+SHA-1
+SHA-224
+SHA-256
+ 1. A known answer test using a 56 byte string is run.
+ 2. A known answer test using a string of one million letters "a"
+ is run.
+ ('cipher/sha1.c:selftests_sha1',
+ 'cipher/sha256.c:selftests_sha224',
+ 'cipher/sha256.c:selftests_sha256')
+SHA-384
+SHA-512
+ 1. A known answer test using a 112 byte string is run.
+ 2. A known answer test using a string of one million letters "a"
+ is run.
+ ('cipher/sha512.c:selftests_sha384',
+ 'cipher/sha512.c:selftests_sha512')
+
+A.3.3 MAC Algorithm Tests
+-------------------------
+
+The following MAC algorithm tests are run in addition to the power-up
+tests:
+
+HMAC SHA-1
+ 1. A known answer test using 9 byte of data and a 20 byte key is
+ run.
+ 2. A known answer test using 9 byte of data and a 100 byte key is
+ run.
+ 3. A known answer test using 9 byte of data and a 49 byte key is
+ run.
+ ('cipher/hmac-tests.c:selftests_sha1')
+HMAC SHA-224
+HMAC SHA-256
+HMAC SHA-384
+HMAC SHA-512
+ 1. A known answer test using 9 byte of data and a 20 byte key is
+ run.
+ 2. A known answer test using 50 byte of data and a 20 byte key is
+ run.
+ 3. A known answer test using 50 byte of data and a 26 byte key is
+ run.
+ 4. A known answer test using 54 byte of data and a 131 byte key
+ is run.
+ 5. A known answer test using 152 byte of data and a 131 byte key
+ is run.
+ ('cipher/hmac-tests.c:selftests_sha224',
+ 'cipher/hmac-tests.c:selftests_sha256',
+ 'cipher/hmac-tests.c:selftests_sha384',
+ 'cipher/hmac-tests.c:selftests_sha512')
+
+\1f
+File: gcrypt.info, Node: FIPS Mode, Next: Library Copying, Prev: Self-Tests, Up: Top
+
+Appendix B Description of the FIPS Mode
+***************************************
+
+This appendix gives detailed information pertaining to the FIPS mode.
+In particular, the changes to the standard mode and the finite state
+machine are described. The self-tests required in this mode are
+described in the appendix on self-tests.
+
+B.1 Restrictions in FIPS Mode
+=============================
+
+If Libgcrypt is used in FIPS mode these restrictions are effective:
+
+ * The cryptographic algorithms are restricted to this list:
+
+ GCRY_CIPHER_3DES
+ 3 key EDE Triple-DES symmetric encryption.
+ GCRY_CIPHER_AES128
+ AES 128 bit symmetric encryption.
+ GCRY_CIPHER_AES192
+ AES 192 bit symmetric encryption.
+ GCRY_CIPHER_AES256
+ AES 256 bit symmetric encryption.
+ GCRY_MD_SHA1
+ SHA-1 message digest.
+ GCRY_MD_SHA224
+ SHA-224 message digest.
+ GCRY_MD_SHA256
+ SHA-256 message digest.
+ GCRY_MD_SHA384
+ SHA-384 message digest.
+ GCRY_MD_SHA512
+ SHA-512 message digest.
+ GCRY_MD_SHA1,GCRY_MD_FLAG_HMAC
+ HMAC using a SHA-1 message digest.
+ GCRY_MD_SHA224,GCRY_MD_FLAG_HMAC
+ HMAC using a SHA-224 message digest.
+ GCRY_MD_SHA256,GCRY_MD_FLAG_HMAC
+ HMAC using a SHA-256 message digest.
+ GCRY_MD_SHA384,GCRY_MD_FLAG_HMAC
+ HMAC using a SHA-384 message digest.
+ GCRY_MD_SHA512,GCRY_MD_FLAG_HMAC
+ HMAC using a SHA-512 message digest.
+ GCRY_PK_RSA
+ RSA encryption and signing.
+ GCRY_PK_DSA
+ DSA signing.
+
+ Note that the CRC algorithms are not considered cryptographic
+ algorithms and thus are in addition available.
+
+ * RSA key generation refuses to create a key with a keysize of less
+ than 1024 bits.
+
+ * DSA key generation refuses to create a key with a keysize other
+ than 1024 bits.
+
+ * The 'transient-key' flag for RSA and DSA key generation is ignored.
+
+ * Support for the VIA Padlock engine is disabled.
+
+ * FIPS mode may only be used on systems with a /dev/random device.
+ Switching into FIPS mode on other systems will fail at runtime.
+
+ * Saving and loading a random seed file is ignored.
+
+ * An X9.31 style random number generator is used in place of the
+ large-pool-CSPRNG generator.
+
+ * The command 'GCRYCTL_ENABLE_QUICK_RANDOM' is ignored.
+
+ * Message digest debugging is disabled.
+
+ * All debug output related to cryptographic data is suppressed.
+
+ * On-the-fly self-tests are not performed, instead self-tests are run
+ before entering operational state.
+
+ * The function 'gcry_set_allocation_handler' may not be used. If it
+ is used Libgcrypt disables FIPS mode unless Enforced FIPS mode is
+ enabled, in which case Libgcrypt will enter the error state.
+
+ * The digest algorithm MD5 may not be used. If it is used Libgcrypt
+ disables FIPS mode unless Enforced FIPS mode is enabled, in which
+ case Libgcrypt will enter the error state.
+
+ * In Enforced FIPS mode the command 'GCRYCTL_DISABLE_SECMEM' is
+ ignored. In standard FIPS mode it disables FIPS mode.
+
+ * A handler set by 'gcry_set_outofcore_handler' is ignored.
+ * A handler set by 'gcry_set_fatalerror_handler' is ignored.
+
+ Note that when we speak about disabling FIPS mode, it merely means
+that the function 'gcry_fips_mode_active' returns false; it does not
+mean that any non FIPS algorithms are allowed.
+
+B.2 FIPS Finite State Machine
+=============================
+
+The FIPS mode of libgcrypt implements a finite state machine (FSM) using
+8 states (*note Table B.1: tbl:fips-states.) and checks at runtime that
+only valid transitions (*note Table B.2: tbl:fips-state-transitions.)
+may happen.
+
+ \0\b[image src="fips-fsm.png" alt="FIPS FSM Diagram"\0\b]
+
+Figure B.1: FIPS mode state diagram
+
+States used by the FIPS FSM:
+
+Power-Off
+ Libgcrypt is not runtime linked to another application. This
+ usually means that the library is not loaded into main memory.
+ This state is documentation only.
+
+Power-On
+ Libgcrypt is loaded into memory and API calls may be made.
+ Compiler introduced constructor functions may be run. Note that
+ Libgcrypt does not implement any arbitrary constructor functions to
+ be called by the operating system
+
+Init
+ The Libgcrypt initialization functions are performed and the
+ library has not yet run any self-test.
+
+Self-Test
+ Libgcrypt is performing self-tests.
+
+Operational
+ Libgcrypt is in the operational state and all interfaces may be
+ used.
+
+Error
+ Libgrypt is in the error state. When calling any FIPS relevant
+ interfaces they either return an error ('GPG_ERR_NOT_OPERATIONAL')
+ or put Libgcrypt into the Fatal-Error state and won't return.
+
+Fatal-Error
+ Libgcrypt is in a non-recoverable error state and will
+ automatically transit into the Shutdown state.
+
+Shutdown
+ Libgcrypt is about to be terminated and removed from the memory.
+ The application may at this point still running cleanup handlers.
+
+Table B.1: FIPS mode states
+
+The valid state transitions (*note Figure B.1: fig:fips-fsm.) are:
+'1'
+ Power-Off to Power-On is implicitly done by the OS loading
+ Libgcrypt as a shared library and having it linked to an
+ application.
+
+'2'
+ Power-On to Init is triggered by the application calling the
+ Libgcrypt initialization function 'gcry_check_version'.
+
+'3'
+ Init to Self-Test is either triggered by a dedicated API call or
+ implicit by invoking a libgrypt service controlled by the FSM.
+
+'4'
+ Self-Test to Operational is triggered after all self-tests passed
+ successfully.
+
+'5'
+ Operational to Shutdown is an artificial state without any direct
+ action in Libgcrypt. When reaching the Shutdown state the library
+ is deinitialized and can't return to any other state again.
+
+'6'
+ Shutdown to Power-off is the process of removing Libgcrypt from the
+ computer's memory. For obvious reasons the Power-Off state can't
+ be represented within Libgcrypt and thus this transition is for
+ documentation only.
+
+'7'
+ Operational to Error is triggered if Libgcrypt detected an
+ application error which can't be returned to the caller but still
+ allows Libgcrypt to properly run. In the Error state all FIPS
+ relevant interfaces return an error code.
+
+'8'
+ Error to Shutdown is similar to the Operational to Shutdown
+ transition (5).
+
+'9'
+ Error to Fatal-Error is triggered if Libgrypt detects an fatal
+ error while already being in Error state.
+
+'10'
+ Fatal-Error to Shutdown is automatically entered by Libgcrypt after
+ having reported the error.
+
+'11'
+ Power-On to Shutdown is an artificial state to document that
+ Libgcrypt has not ye been initialized but the process is about to
+ terminate.
+
+'12'
+ Power-On to Fatal-Error will be triggered if certain Libgcrypt
+ functions are used without having reached the Init state.
+
+'13'
+ Self-Test to Fatal-Error is triggered by severe errors in Libgcrypt
+ while running self-tests.
+
+'14'
+ Self-Test to Error is triggered by a failed self-test.
+
+'15'
+ Operational to Fatal-Error is triggered if Libcrypt encountered a
+ non-recoverable error.
+
+'16'
+ Operational to Self-Test is triggered if the application requested
+ to run the self-tests again.
+
+'17'
+ Error to Self-Test is triggered if the application has requested to
+ run self-tests to get to get back into operational state after an
+ error.
+
+'18'
+ Init to Error is triggered by errors in the initialization code.
+
+'19'
+ Init to Fatal-Error is triggered by non-recoverable errors in the
+ initialization code.
+
+'20'
+ Error to Error is triggered by errors while already in the Error
+ state.
+
+Table B.2: FIPS mode state transitions
+
+B.3 FIPS Miscellaneous Information
+==================================
+
+Libgcrypt does not do any key management on itself; the application
+needs to care about it. Keys which are passed to Libgcrypt should be
+allocated in secure memory as available with the functions
+'gcry_malloc_secure' and 'gcry_calloc_secure'. By calling 'gcry_free'
+on this memory, the memory and thus the keys are overwritten with zero
+bytes before releasing the memory.
+
+ For use with the random number generator, Libgcrypt generates 3
+internal keys which are stored in the encryption contexts used by the
+RNG. These keys are stored in secure memory for the lifetime of the
+process. Application are required to use 'GCRYCTL_TERM_SECMEM' before
+process termination. This will zero out the entire secure memory and
+thus also the encryption contexts with these keys.
+
+\1f
+File: gcrypt.info, Node: Library Copying, Next: Copying, Prev: FIPS Mode, Up: Top
+
+GNU Lesser General Public License
+*********************************
+
+ Version 2.1, February 1999
+
+ Copyright (C) 1991, 1999 Free Software Foundation, Inc.
+ 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ [This is the first released version of the Lesser GPL. It also counts
+ as the successor of the GNU Library Public License, version 2, hence the
+ version number 2.1.]
+
+Preamble
+========
+
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+ LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS
+ AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+ OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND
+ PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE
+ DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR
+ OR CORRECTION.
+
+ 13. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
+ WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY
+ MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE
+ LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL,
+ INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR
+ INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+ DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU
+ OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY
+ OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN
+ ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+
+ END OF TERMS AND CONDITIONS
+
+How to Apply These Terms to Your New Programs
+=============================================
+
+If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these
+terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least the
+"copyright" line and a pointer to where the full notice is found.
+
+ ONE LINE TO GIVE THE PROGRAM'S NAME AND AN IDEA OF WHAT IT DOES.
+ Copyright (C) 19YY NAME OF AUTHOR
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ as published by the Free Software Foundation; either version 2
+ of the License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+
+ Also add information on how to contact you by electronic and paper
+mail.
+
+ If the program is interactive, make it output a short notice like
+this when it starts in an interactive mode:
+
+ Gnomovision version 69, Copyright (C) 19YY NAME OF AUTHOR
+ Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
+ type `show w'. This is free software, and you are welcome
+ to redistribute it under certain conditions; type `show c'
+ for details.
+
+ The hypothetical commands 'show w' and 'show c' should show the
+appropriate parts of the General Public License. Of course, the
+commands you use may be called something other than 'show w' and 'show
+c'; they could even be mouse-clicks or menu items--whatever suits your
+program.
+
+ You should also get your employer (if you work as a programmer) or
+your school, if any, to sign a "copyright disclaimer" for the program,
+if necessary. Here is a sample; alter the names:
+
+ Yoyodyne, Inc., hereby disclaims all copyright
+ interest in the program `Gnomovision'
+ (which makes passes at compilers) written
+ by James Hacker.
+
+ SIGNATURE OF TY COON, 1 April 1989
+ Ty Coon, President of Vice
+
+ This General Public License does not permit incorporating your
+program into proprietary programs. If your program is a subroutine
+library, you may consider it more useful to permit linking proprietary
+applications with the library. If this is what you want to do, use the
+GNU Library General Public License instead of this License.
+
+\1f
+File: gcrypt.info, Node: Figures and Tables, Next: Concept Index, Prev: Copying, Up: Top
+
+List of Figures and Tables
+**************************
+
+* Menu:
+
+* Figure 17.1: fig:subsystems. Libgcrypt subsystems
+* Figure B.1: fig:fips-fsm. FIPS mode state diagram
+
+* Menu:
+
+* Table B.1: tbl:fips-states. FIPS mode states
+* Table B.2: tbl:fips-state-transitions. FIPS mode state transitions
+
+\1f
+File: gcrypt.info, Node: Concept Index, Next: Function and Data Index, Prev: Figures and Tables, Up: Top
+
+Concept Index
+*************
+
+\0\b[index\0\b]
+* Menu:
+
+* /etc/gcrypt/fips_enabled: Configuration. (line 69)
+* /etc/gcrypt/hwf.deny: Configuration. (line 48)
+* /etc/gcrypt/random.conf: Configuration. (line 52)
+* /proc/cpuinfo: Configuration. (line 74)
+* /proc/self/auxv: Configuration. (line 74)
+* 3DES: Available ciphers. (line 14)
+* Advanced Encryption Standard: Available ciphers. (line 35)
+* AES: Available ciphers. (line 35)
+* AES-Wrap mode: Available cipher modes.
+ (line 35)
+* Arcfour: Available ciphers. (line 52)
+* BLAKE2b-512, BLAKE2b-384, BLAKE2b-256, BLAKE2b-160: Available hash algorithms.
+ (line 6)
+* BLAKE2s-256, BLAKE2s-224, BLAKE2s-160, BLAKE2s-128: Available hash algorithms.
+ (line 6)
+* Blowfish: Available ciphers. (line 22)
+* bug emulation: Working with hash algorithms.
+ (line 38)
+* Camellia: Available ciphers. (line 77)
+* CAST5: Available ciphers. (line 19)
+* CBC, Cipher Block Chaining mode: Available cipher modes.
+ (line 23)
+* CBC-MAC: Working with cipher handles.
+ (line 56)
+* CCM, Counter with CBC-MAC mode: Available cipher modes.
+ (line 48)
+* CFB, Cipher Feedback mode: Available cipher modes.
+ (line 17)
+* ChaCha20: Available ciphers. (line 92)
+* cipher text stealing: Working with cipher handles.
+ (line 50)
+* comp: Cryptographic Functions.
+ (line 13)
+* CRC32: Available hash algorithms.
+ (line 6)
+* CTR, Counter mode: Available cipher modes.
+ (line 32)
+* DES: Available ciphers. (line 57)
+* DES-EDE: Available ciphers. (line 14)
+* Digital Encryption Standard: Available ciphers. (line 14)
+* disable-jent: Configuration. (line 58)
+* ECB, Electronic Codebook mode: Available cipher modes.
+ (line 13)
+* EdDSA: Cryptographic Functions.
+ (line 33)
+* Enforced FIPS mode: Enabling FIPS mode. (line 29)
+* error codes: Error Values. (line 6)
+* error codes, list of: Error Sources. (line 6)
+* error codes, list of <1>: Error Codes. (line 6)
+* error codes, printing of: Error Strings. (line 6)
+* error sources: Error Values. (line 6)
+* error sources, printing of: Error Strings. (line 6)
+* error strings: Error Strings. (line 6)
+* error values: Error Values. (line 6)
+* error values, printing of: Error Strings. (line 6)
+* FIPS 140: Enabling FIPS mode. (line 6)
+* FIPS 186: Cryptographic Functions.
+ (line 72)
+* FIPS 186 <1>: Public-Key Subsystem Architecture.
+ (line 50)
+* FIPS 186-2: Cryptographic Functions.
+ (line 80)
+* FIPS mode: Enabling FIPS mode. (line 6)
+* fips_enabled: Configuration. (line 69)
+* GCM, Galois/Counter Mode: Available cipher modes.
+ (line 53)
+* GCRYPT_BARRETT: Configuration. (line 12)
+* GCRYPT_RNDUNIX_DBG: Configuration. (line 17)
+* GCRYPT_RNDUNIX_DBGALL: Configuration. (line 17)
+* GCRYPT_RNDW32_DBG: Configuration. (line 32)
+* GCRYPT_RNDW32_NOPERF: Configuration. (line 25)
+* GOST 28147-89: Available ciphers. (line 88)
+* GPL, GNU General Public License: Copying. (line 6)
+* hardware features: Hardware features. (line 6)
+* HAVAL: Available hash algorithms.
+ (line 6)
+* HMAC: Working with hash algorithms.
+ (line 28)
+* HMAC-GOSTR-3411-94: Available MAC algorithms.
+ (line 6)
+* HMAC-MD2, HMAC-MD4, HMAC-MD5: Available MAC algorithms.
+ (line 6)
+* HMAC-RIPE-MD-160: Available MAC algorithms.
+ (line 6)
+* HMAC-SHA-1: Available MAC algorithms.
+ (line 6)
+* HMAC-SHA-224, HMAC-SHA-256, HMAC-SHA-384, HMAC-SHA-512: Available MAC algorithms.
+ (line 6)
+* HMAC-SHA3-224, HMAC-SHA3-256, HMAC-SHA3-384, HMAC-SHA3-512: Available MAC algorithms.
+ (line 6)
+* HMAC-Stribog-256, HMAC-Stribog-512: Available MAC algorithms.
+ (line 6)
+* HMAC-TIGER1: Available MAC algorithms.
+ (line 6)
+* HMAC-Whirlpool: Available MAC algorithms.
+ (line 6)
+* HOME: Configuration. (line 37)
+* IDEA: Available ciphers. (line 11)
+* LGPL, GNU Lesser General Public License: Library Copying. (line 6)
+* MD2, MD4, MD5: Available hash algorithms.
+ (line 6)
+* no-blinding: Cryptographic Functions.
+ (line 41)
+* no-keytest: Cryptographic Functions.
+ (line 59)
+* nocomp: Cryptographic Functions.
+ (line 13)
+* OAEP: Cryptographic Functions.
+ (line 27)
+* OCB, OCB3: Available cipher modes.
+ (line 63)
+* OFB, Output Feedback mode: Available cipher modes.
+ (line 29)
+* only-urandom: Configuration. (line 61)
+* param: Cryptographic Functions.
+ (line 47)
+* PKCS1: Cryptographic Functions.
+ (line 23)
+* Poly1305 based AEAD mode with ChaCha20: Available cipher modes.
+ (line 58)
+* PSS: Cryptographic Functions.
+ (line 30)
+* RC2: Available ciphers. (line 69)
+* RC4: Available ciphers. (line 52)
+* rfc-2268: Available ciphers. (line 69)
+* RFC6979: Cryptographic Functions.
+ (line 38)
+* Rijndael: Available ciphers. (line 35)
+* RIPE-MD-160: Available hash algorithms.
+ (line 6)
+* Salsa20: Available ciphers. (line 81)
+* Salsa20/12: Available ciphers. (line 84)
+* Seed (cipher): Available ciphers. (line 72)
+* Serpent: Available ciphers. (line 65)
+* SHA-1: Available hash algorithms.
+ (line 6)
+* SHA-224, SHA-256, SHA-384, SHA-512: Available hash algorithms.
+ (line 6)
+* SHA3-224, SHA3-256, SHA3-384, SHA3-512, SHAKE128, SHAKE256: Available hash algorithms.
+ (line 6)
+* sync mode (OpenPGP): Working with cipher handles.
+ (line 46)
+* TIGER, TIGER1, TIGER2: Available hash algorithms.
+ (line 6)
+* transient-key: Cryptographic Functions.
+ (line 52)
+* Triple-DES: Available ciphers. (line 14)
+* Twofish: Available ciphers. (line 46)
+* Whirlpool: Available hash algorithms.
+ (line 6)
+* X9.31: Cryptographic Functions.
+ (line 65)
+* X9.31 <1>: Public-Key Subsystem Architecture.
+ (line 50)
+* XTS, XTS mode: Available cipher modes.
+ (line 74)
+
/* Allocate a pool of 16k secure memory. This makes the secure memory
available and also drops privileges where needed. Note that by
using functions like gcry_xmalloc_secure and gcry_mpi_snew Libgcrypt
- may extend the secure memory pool with memory which lacks the
+ may expand the secure memory pool with memory which lacks the
property of not being swapped out to disk. */
gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
Disabling the use of mlock may for example be done if an encrypted
swap space is in use. This command should be executed right after
@code{gcry_check_version}. Note that by using functions like
-gcry_xmalloc_secure and gcry_mpi_snew Libgcrypt may extend the secure
+gcry_xmalloc_secure and gcry_mpi_snew Libgcrypt may expand the secure
memory pool with memory which lacks the property of not being swapped
out to disk (but will still be zeroed out on free).
command has been used the caller is responsible for dropping the
privileges.
-@item GCRYCTL_INIT_SECMEM; Arguments: int nbytes
+@item GCRYCTL_INIT_SECMEM; Arguments: unsigned int nbytes
This command is used to allocate a pool of secure memory and thus
enabling the use of secure memory. It also drops all extra privileges
the process has (i.e. if it is run as setuid (root)). If the argument
an error, an according error code is returned.
The ID of algorithm to use must be specified via @var{algo}. See
-@xref{Available ciphers}, for a list of supported ciphers and the
+@ref{Available ciphers}, for a list of supported ciphers and the
according constants.
Besides using the constants directly, the function
an algorithm into the according numeric ID.
The cipher mode to use must be specified via @var{mode}. See
-@xref{Available cipher modes}, for a list of supported cipher modes
+@ref{Available cipher modes}, for a list of supported cipher modes
and the according constants. Note that some modes are incompatible
with some algorithms - in particular, stream mode
(@code{GCRY_CIPHER_MODE_STREAM}) only works with stream ciphers.
Where @var{r-mpi} and @var{s-mpi} are the result of the DSA sign
operation.
-For Elgamal signing (which is slow, yields large numbers and probably
-is not as secure as the other algorithms), the same format is used
-with "elg" replacing "dsa"; for ECDSA signing, the same format is used
-with "ecdsa" replacing "dsa".
+For Elgamal signing (which is slow, yields large numbers, hard to use
+correctly and probably is not as secure as the other algorithms), the
+same format is used with "elg" replacing "dsa"; for ECDSA signing, the
+same format is used with "ecdsa" replacing "dsa".
For the EdDSA algorithm (cf. Ed25515) the required input parameters are:
@noindent
If this parameter is not used, Libgcrypt uses for historic reasons
-65537.
+65537. Note that the value must fit into a 32 bit unsigned variable
+and that the usual C prefixes are considered (e.g. 017 gives 15).
+
@item qbits @var{n}
This is only meanigful for DSA keys. If it is given the DSA key is
@code{gcry_md_enable}. @var{hd} is guaranteed to either receive a valid
handle or NULL.
-For a list of supported algorithms, see @xref{Available hash
+For a list of supported algorithms, see @ref{Available hash
algorithms}.
The flags allowed for @var{mode} are:
@code{gcry_md_setkey} must be used to set the MAC key. The size of the
MAC is equal to the message digest of the underlying hash algorithm.
If you want CBC message authentication codes based on a cipher,
-see @xref{Working with cipher handles}.
+see @ref{Working with cipher handles}.
@item GCRY_MD_FLAG_BUGEMU1
@cindex bug emulation
receive a valid handle or NULL. @var{ctx} is context object to associate MAC
object with. @var{ctx} maybe set to NULL.
-For a list of supported algorithms, see @xref{Available MAC algorithms}.
+For a list of supported algorithms, see @ref{Available MAC algorithms}.
The flags allowed for @var{mode} are:
required by different algorithms S-expressions, as flexible way to
convey these parameters, are used. There is a set of helper functions
to work with these S-expressions.
-@c see @xref{S-expression Subsystem Architecture}.
+@c see @ref{S-expression Subsystem Architecture}.
Aside of functions to register new algorithms, map algorithms names to
algorithms identifiers and to lookup properties of a key, the
%!PS-Adobe-3.0 EPSF-3.0
-%%Title: /home/wk/s/libgcrypt/doc/libgcrypt-modules.fig
+%%Title: /home/wk/s/libgcrypt-1.8/doc/libgcrypt-modules.fig
%%Creator: fig2dev Version 3.2 Patchlevel 5e
-%%CreationDate: Tue Jan 6 19:07:13 2015
+%%CreationDate: Thu Nov 23 19:46:17 2017
%%BoundingBox: 0 0 488 300
%Magnification: 1.0000
%%EndComments
-@set UPDATED 18 July 2017
-@set UPDATED-MONTH July 2017
-@set EDITION 1.8.1
-@set VERSION 1.8.1
+@set UPDATED 13 June 2018
+@set UPDATED-MONTH June 2018
+@set EDITION 1.8.3
+@set VERSION 1.8.3
-@set UPDATED 18 July 2017
-@set UPDATED-MONTH July 2017
-@set EDITION 1.8.1
-@set VERSION 1.8.1
+@set UPDATED 13 June 2018
+@set UPDATED-MONTH June 2018
+@set EDITION 1.8.3
+@set VERSION 1.8.3
y = mpi_new (0);
w = mpi_new (0);
+ /* Check that the point is in range. This needs to be done here and
+ * not after conversion to affine coordinates. */
+ if (mpi_cmpabs (point->x, ctx->p) >= 0)
+ goto leave;
+ if (mpi_cmpabs (point->y, ctx->p) >= 0)
+ goto leave;
+ if (mpi_cmpabs (point->z, ctx->p) >= 0)
+ goto leave;
+
switch (ctx->model)
{
case MPI_EC_WEIERSTRASS:
************** MIPS/64 **************
***************************************/
#if (defined (__mips) && __mips >= 3) && W_TYPE_SIZE == 64
-# if (__GNUC__ >= 5) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)
+# if defined (__clang__) || (__GNUC__ >= 5) || (__GNUC__ == 4 && \
+ __GNUC_MINOR__ >= 4)
typedef unsigned int UTItype __attribute__ ((mode (TI)));
# define umul_ppmm(w1, w0, u, v) \
do { \
}
-int
-_gcry_mpi_cmp (gcry_mpi_t u, gcry_mpi_t v)
+/* Helper for _gcry_mpi_cmp and _gcry_mpi_cmpabs. */
+static int
+do_mpi_cmp (gcry_mpi_t u, gcry_mpi_t v, int absmode)
{
mpi_size_t usize;
mpi_size_t vsize;
+ int usign;
+ int vsign;
int cmp;
if (mpi_is_opaque (u) || mpi_is_opaque (v))
{
+ /* We have no signan and thus ABSMODE has no efeect here. */
if (mpi_is_opaque (u) && !mpi_is_opaque (v))
return -1;
if (!mpi_is_opaque (u) && mpi_is_opaque (v))
usize = u->nlimbs;
vsize = v->nlimbs;
+ usign = absmode? 0 : u->sign;
+ vsign = absmode? 0 : v->sign;
/* Compare sign bits. */
- if (!u->sign && v->sign)
+ if (!usign && vsign)
return 1;
- if (u->sign && !v->sign)
+ if (usign && !vsign)
return -1;
/* U and V are either both positive or both negative. */
- if (usize != vsize && !u->sign && !v->sign)
+ if (usize != vsize && !usign && !vsign)
return usize - vsize;
- if (usize != vsize && u->sign && v->sign)
+ if (usize != vsize && usign && vsign)
return vsize + usize;
if (!usize )
return 0;
if (!(cmp = _gcry_mpih_cmp (u->d, v->d, usize)))
return 0;
- if ((cmp < 0?1:0) == (u->sign?1:0))
+ if ((cmp < 0?1:0) == (usign?1:0))
return 1;
}
return -1;
}
+
+
+int
+_gcry_mpi_cmp (gcry_mpi_t u, gcry_mpi_t v)
+{
+ return do_mpi_cmp (u, v, 0);
+}
+
+/* Compare only the absolute values. */
+int
+_gcry_mpi_cmpabs (gcry_mpi_t u, gcry_mpi_t v)
+{
+ return do_mpi_cmp (u, v, 1);
+}
{
if (r_active)
{
+ lock_rng ();
/* Make sure the RNG is initialized. */
_gcry_rndjent_poll (NULL, 0, 0);
/* To ease debugging we store 2 for a clock_gettime based
* implementation and 1 for a rdtsc based code. */
*r_active = jent_rng_collector? is_rng_available () : 0;
+ unlock_rng ();
}
return jent_version ();
}
On AMD64, TSC is always available and intrinsic is provided for accessing
it. */
-#ifdef __WIN64__
+#ifdef __x86_64__
{
unsigned __int64 aint64;
(*add) (&aword, sizeof (aword), origin );
}
}
-#endif /*__WIN64__*/
+#endif /*__x86_64__*/
}
void _gcry_mpi_neg (gcry_mpi_t w, gcry_mpi_t u);
void _gcry_mpi_abs (gcry_mpi_t w);
int _gcry_mpi_cmp (const gcry_mpi_t u, const gcry_mpi_t v);
+int _gcry_mpi_cmpabs (const gcry_mpi_t u, const gcry_mpi_t v);
int _gcry_mpi_cmp_ui (const gcry_mpi_t u, unsigned long v);
gpg_err_code_t _gcry_mpi_scan (gcry_mpi_t *ret_mpi, enum gcry_mpi_format format,
const void *buffer, size_t buflen,
#define mpi_abs( w ) _gcry_mpi_abs( (w) )
#define mpi_neg( w, u) _gcry_mpi_neg( (w), (u) )
#define mpi_cmp( u, v ) _gcry_mpi_cmp( (u), (v) )
+#define mpi_cmpabs( u, v ) _gcry_mpi_cmpabs( (u), (v) )
#define mpi_cmp_ui( u, v ) _gcry_mpi_cmp_ui( (u), (v) )
#define mpi_is_neg( a ) _gcry_mpi_is_neg ((a))
& ~GCRY_SECMEM_FLAG_SUSPEND_WARNING));
break;
+ case 78: /* GCRYCTL_AUTO_EXPAND_SECMEM (backport from 1.9) */
+ _gcry_secmem_set_auto_expand (va_arg (arg_ptr, unsigned int));
+ break;
+
case GCRYCTL_USE_SECURE_RNDPOOL:
global_init ();
_gcry_secure_random_alloc (); /* Put random number into secure memory. */
internal consistency checks. It should not be used for sensitive
data because no mechanisms to clear the stack etc are used.
- This module may be used standalone and requires only a few
- standard definitions to be provided in a config.h file.
+ This module may be used standalone.
Types:
for testing this included module.
*/
+#ifdef STANDALONE
+#include <stdint.h>
+#define HAVE_U32_TYPEDEF 1
+typedef uint32_t u32;
+#define VERSION "standalone"
+/* For GCC, we can detect endianness. If not GCC, please define manually. */
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define WORDS_BIGENDIAN 1
+#endif
+#else
#include <config.h>
+#endif
+
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
# include <fcntl.h> /* We need setmode(). */
#endif
-/* For a native WindowsCE binary we need to include gpg-error.h to
- provide a replacement for strerror. In other cases we need a
- replacement macro for gpg_err_set_errno. */
-#ifdef __MINGW32CE__
-# include <gpg-error.h>
+#ifdef STANDALONE
+#define xtrymalloc(a) malloc((a))
+#define gpg_err_set_errno(a) (errno = (a))
#else
-# define gpg_err_set_errno(a) (errno = (a))
+#include "g10lib.h"
#endif
#include "hmac256.h"
{
hmac256_context_t hd;
- hd = malloc (sizeof *hd);
+ hd = xtrymalloc (sizeof *hd);
if (!hd)
return NULL;
}
buffer_size = 32768;
- buffer = malloc (buffer_size);
+ buffer = xtrymalloc (buffer_size);
if (!buffer)
{
fclose (fp);
static pooldesc_t mainpool;
-/* A couple of flags whith some being set early. */
+/* A couple of flags with some being set early. */
static int disable_secmem;
static int show_warning;
static int not_locked;
static int suspend_warning;
static int no_mlock;
static int no_priv_drop;
+static unsigned int auto_expand;
+
/* Lock protecting accesses to the memory pools. */
GPGRT_LOCK_DEFINE (secmem_lock);
# else
pgsize_val = -1;
# endif
- pgsize = (pgsize_val != -1 && pgsize_val > 0)? pgsize_val:DEFAULT_PAGE_SIZE;
+ pgsize = (pgsize_val > 0)? pgsize_val:DEFAULT_PAGE_SIZE;
pool->size = (pool->size + pgsize - 1) & ~(pgsize - 1);
# ifdef MAP_ANONYMOUS
mb->flags = 0;
}
+
+/* Enable overflow pool allocation in all cases. CHUNKSIZE is a hint
+ * on how large to allocate overflow pools. */
+void
+_gcry_secmem_set_auto_expand (unsigned int chunksize)
+{
+ /* Round up to a multiple of the STANDARD_POOL_SIZE. */
+ chunksize = ((chunksize + (2*STANDARD_POOL_SIZE) - 1)
+ / STANDARD_POOL_SIZE ) * STANDARD_POOL_SIZE;
+ if (chunksize < STANDARD_POOL_SIZE) /* In case of overflow. */
+ chunksize = STANDARD_POOL_SIZE;
+
+ SECMEM_LOCK;
+ auto_expand = chunksize;
+ SECMEM_UNLOCK;
+}
+
+
void
_gcry_secmem_set_flags (unsigned flags)
{
/* If we are called from xmalloc style function resort to the
* overflow pools to return memory. We don't do this in FIPS mode,
* though. */
- if (xhint && !fips_mode ())
+ if ((xhint || auto_expand) && !fips_mode ())
{
for (pool = pool->next; pool; pool = pool->next)
{
pool = calloc (1, sizeof *pool);
if (!pool)
return NULL; /* Not enough memory for a new pool descriptor. */
- pool->size = STANDARD_POOL_SIZE;
+ pool->size = auto_expand? auto_expand : STANDARD_POOL_SIZE;
pool->mem = malloc (pool->size);
if (!pool->mem)
return NULL; /* Not enough memory available for a new pool. */
void *_gcry_secmem_realloc (void *a, size_t newsize, int xhint);
int _gcry_secmem_free (void *a);
void _gcry_secmem_dump_stats (int extended);
+void _gcry_secmem_set_auto_expand (unsigned int chunksize);
void _gcry_secmem_set_flags (unsigned flags);
unsigned _gcry_secmem_get_flags(void);
int _gcry_private_is_secure (const void *p);
/* sexp.c - S-Expression handling
* Copyright (C) 1999, 2000, 2001, 2002, 2003,
* 2004, 2006, 2007, 2008, 2011 Free Software Foundation, Inc.
- * Copyright (C) 2013, 2014 g10 Code GmbH
+ * Copyright (C) 2013, 2014, 2017 g10 Code GmbH
*
* This file is part of Libgcrypt.
*
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
- * You should have received a copy of the GNU Lesser General Public
- * License along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ * SPDX-License-Identifier: LGPL-2.1+
*/
/****************
* Append n to the list a
- * Returns: a new ist (which maybe a)
+ * Returns: a new list (which maybe a)
*/
gcry_sexp_t
_gcry_sexp_append( const gcry_sexp_t a, const gcry_sexp_t n )
}
else
{
- if (_gcry_mpi_print (mpifmt, NULL, 0, &nm, m))
- BUG ();
+ err = _gcry_mpi_print (mpifmt, NULL, 0, &nm, m);
+ if (err)
+ goto leave;
MAKE_SPACE (nm);
if (!_gcry_is_secure (c.sexp->d)
*c.pos++ = ST_DATA;
STORE_LEN (c.pos, nm);
- if (_gcry_mpi_print (mpifmt, c.pos, nm, &nm, m))
- BUG ();
+ err = _gcry_mpi_print (mpifmt, c.pos, nm, &nm, m);
+ if (err)
+ goto leave;
c.pos += nm;
}
}
char buf[35];
ARG_NEXT (aint, int);
- sprintf (buf, "%d", aint);
+ snprintf (buf, sizeof buf, "%d", aint);
alen = strlen (buf);
MAKE_SPACE (alen);
*c.pos++ = ST_DATA;
char buf[35];
ARG_NEXT (aint, unsigned int);
- sprintf (buf, "%u", aint);
+ snprintf (buf, sizeof buf, "%u", aint);
alen = strlen (buf);
MAKE_SPACE (alen);
*c.pos++ = ST_DATA;
{
*dest++ = '#';
for (i=0; i < len; i++, dest += 2 )
- sprintf (dest, "%02X", src[i]);
+ snprintf (dest, 3, "%02X", src[i]);
*dest++ = '#';
}
return len*2+2;
default:
if ( (*s < 0x20 || (*s >= 0x7f && *s <= 0xa0)))
{
- sprintf (p, "\\x%02x", *s);
+ snprintf (p, 5, "\\x%02x", *s);
p += 4;
}
else
}
else
{
- sprintf (numbuf, "%u:", (unsigned int)n );
+ snprintf (numbuf, sizeof numbuf, "%u:", (unsigned int)n );
len += strlen (numbuf) + n;
if ( buffer )
{
VALUE "FileDescription", "Libgcrypt - The GNU Crypto Library\0"
VALUE "FileVersion", "@LIBGCRYPT_LT_CURRENT@.@LIBGCRYPT_LT_AGE@.@LIBGCRYPT_LT_REVISION@.@BUILD_REVISION@\0"
VALUE "InternalName", "libgcrypt\0"
- VALUE "LegalCopyright", "Copyright © 2017 Free Software Foundation, Inc.\0"
+ VALUE "LegalCopyright", "Copyright © 2018 Free Software Foundation, Inc.\0"
VALUE "LegalTrademarks", "\0"
VALUE "OriginalFilename", "libgcrypt.dll\0"
VALUE "PrivateBuild", "\0"
static void
_check_gcm_cipher (unsigned int step)
{
- struct tv
+#define MAX_GCM_DATA_LEN (256 + 32)
+ static const struct tv
{
int algo;
char key[MAX_DATA_LEN];
int ivlen;
unsigned char aad[MAX_DATA_LEN];
int aadlen;
- unsigned char plaintext[MAX_DATA_LEN];
+ unsigned char plaintext[MAX_GCM_DATA_LEN];
int inlen;
- char out[MAX_DATA_LEN];
+ char out[MAX_GCM_DATA_LEN];
char tag[MAX_DATA_LEN];
int taglen;
int should_fail;
"\xee\xb2\xb2\x2a\xaf\xde\x64\x19\xa0\x58\xab\x4f\x6f\x74\x6b\xf4"
"\x0f\xc0\xc3\xb7\x80\xf2\x44\x45\x2d\xa3\xeb\xf1\xc5\xd8\x2c\xde"
"\xa2\x41\x89\x97\x20\x0e\xf8\x2e\x44\xae\x7e\x3f",
- "\xa4\x4a\x82\x66\xee\x1c\x8e\xb0\xc8\xb5\xd4\xcf\x5a\xe9\xf1\x9a" }
+ "\xa4\x4a\x82\x66\xee\x1c\x8e\xb0\xc8\xb5\xd4\xcf\x5a\xe9\xf1\x9a" },
+ /* Test vectors for overflowing CTR. */
+ /* After setiv, ctr_low: 0xffffffff */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x86\xdd\x40\xe7",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x7d\x6e\x38\xfd\xd0\x04\x9d\x28\xdf\x4a\x10\x3f\xa3\x9e\xf8\xf8"
+ "\x6c\x2c\x10\xa7\x91\xab\xc0\x86\xd4\x6d\x69\xea\x58\xc4\xf9\xc0"
+ "\xd4\xee\xc2\xb0\x9d\x36\xae\xe7\xc9\xa9\x1f\x71\xa8\xee\xa2\x1d"
+ "\x20\xfd\x79\xc7\xd9\xc4\x90\x51\x38\x97\xb6\x9f\x55\xea\xf3\xf0"
+ "\x78\xb4\xd3\x8c\xa9\x9b\x32\x7d\x19\x36\x96\xbc\x8e\xab\x80\x9f"
+ "\x61\x56\xcc\xbd\x3a\x80\xc6\x69\x37\x0a\x89\x89\x21\x82\xb7\x79"
+ "\x6d\xe9\xb4\x34\xc4\x31\xe0\xbe\x71\xad\xf3\x50\x05\xb2\x61\xab"
+ "\xb3\x1a\x80\x57\xcf\xe1\x11\x26\xcb\xa9\xd1\xf6\x58\x46\xf1\x69"
+ "\xa2\xb8\x42\x3c\xe8\x28\x13\xca\x58\xd9\x28\x99\xf8\xc8\x17\x32"
+ "\x4a\xf9\xb3\x4c\x7a\x47\xad\xe4\x77\x64\xec\x70\xa1\x01\x0b\x88"
+ "\xe7\x30\x0b\xbd\x66\x25\x39\x1e\x51\x67\xee\xec\xdf\xb8\x24\x5d"
+ "\x7f\xcb\xee\x7a\x4e\xa9\x93\xf0\xa1\x84\x7b\xfe\x5a\xe3\x86\xb2"
+ "\xfb\xcd\x39\xe7\x1e\x5e\x48\x65\x4b\x50\x2b\x4a\x99\x46\x3f\x6f"
+ "\xdb\xd9\x97\xdb\xe5\x6d\xa4\xdd\x6c\x18\x64\x5e\xae\x7e\x2c\xd3"
+ "\xb4\xf3\x57\x5c\xb5\xf8\x7f\xe5\x87\xb5\x35\xdb\x80\x38\x6e\x2c"
+ "\x5c\xdd\xeb\x7c\x63\xac\xe4\xb5\x5a\x6a\x40\x6d\x72\x69\x9a\xa9"
+ "\x8f\x5e\x93\x91\x4d\xce\xeb\x87\xf5\x25\xed\x75\x6b\x3b\x1a\xf2"
+ "\x0c\xd2\xa4\x10\x45\xd2\x87\xae\x29\x6d\xeb\xea\x66\x5f\xa0\xc2",
+ "\x8c\x22\xe3\xda\x9d\x94\x8a\xbe\x8a\xbc\x55\x2c\x94\x63\x44\x40" },
+ /* After setiv, ctr_low: 0xfffffffe */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x8d\xd1\xc1\xdf",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\xac\x6a\x10\x3f\xe2\x8d\xed\x27\x55\x14\xca\x1f\x03\x67\x0a\xa8"
+ "\xa1\x07\xbf\x00\x73\x5b\x64\xef\xac\x30\x83\x81\x48\x4c\xaa\xd5"
+ "\xff\xca\xef\x2f\x77\xbe\xfe\x1b\x20\x5c\x86\x19\xc7\xf9\x11\x99"
+ "\x27\xc5\x57\xa7\x0a\xc2\xa8\x05\xd9\x07\x2b\xb9\x38\xa4\xef\x58"
+ "\x92\x74\xcf\x89\xc7\xba\xfc\xb9\x70\xac\x86\xe2\x31\xba\x7c\xf9"
+ "\xc4\xe2\xe0\x4c\x1b\xe4\x3f\x75\x83\x5c\x40\x0e\xa4\x13\x8b\x04"
+ "\x60\x78\x57\x29\xbb\xe6\x61\x93\xe3\x16\xf9\x58\x07\x75\xd0\x96"
+ "\xfb\x8f\x6d\x1e\x49\x0f\xd5\x31\x9e\xee\x31\xe6\x0a\x85\x93\x49"
+ "\x22\xcf\xd6\x1b\x40\x44\x63\x9c\x95\xaf\xf0\x44\x23\x51\x37\x92"
+ "\x0d\xa0\x22\x37\xb9\x6d\x13\xf9\x78\xba\x27\x27\xed\x08\x7e\x35"
+ "\xe4\xe2\x28\xeb\x0e\xbe\x3d\xce\x89\x93\x35\x84\x0f\xa0\xf9\x8d"
+ "\x94\xe9\x5a\xec\xd4\x0d\x1f\x5c\xbe\x6f\x8e\x6a\x4d\x10\x65\xbb"
+ "\xc7\x0b\xa0\xd5\x5c\x20\x80\x0b\x4a\x43\xa6\xe1\xb0\xe0\x56\x6a"
+ "\xde\x90\xe0\x6a\x45\xe7\xc2\xd2\x69\x9b\xc6\x62\x11\xe3\x2b\xa5"
+ "\x45\x98\xb0\x80\xd3\x57\x4d\x1f\x09\x83\x58\xd4\x4d\xa6\xc5\x95"
+ "\x87\x59\xb0\x58\x6c\x81\x49\xc5\x95\x18\x23\x1b\x6f\x10\x86\xa2"
+ "\xd9\x56\x19\x30\xec\xd3\x4a\x4b\xe8\x1c\x11\x37\xfb\x31\x60\x4d"
+ "\x4f\x9b\xc4\x95\xba\xda\x49\x43\x6c\xc7\x3d\x5b\x13\xf9\x91\xf8",
+ "\xcd\x2b\x83\xd5\x5b\x5a\x8e\x0b\x2e\x77\x0d\x97\xbf\xf7\xaa\xab" },
+ /* After setiv, ctr_low: 0xfffffffd */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x76\x8c\x18\x92",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x3d\x6f\x4e\xf6\xd2\x6f\x4e\xce\xa6\xb4\x4a\x9e\xcb\x57\x13\x90"
+ "\x51\x3b\xf6\xb2\x40\x55\x0c\x2c\xa2\x85\x44\x72\xf2\x90\xaf\x6b"
+ "\x86\x8c\x75\x2a\x9c\xd6\x52\x50\xee\xc6\x5f\x59\xbc\x8d\x18\xd7"
+ "\x87\xa5\x7f\xa0\x13\xd1\x5d\x54\x77\x30\xe2\x5d\x1b\x4f\x87\x9f"
+ "\x3a\x41\xcb\x6a\xdf\x44\x4f\xa2\x1a\xbc\xfb\x4b\x16\x67\xed\x59"
+ "\x65\xf0\x77\x48\xca\xfd\xf0\xb6\x90\x65\xca\x23\x09\xca\x83\x43"
+ "\x8f\xf0\x78\xb4\x5f\x96\x2a\xfd\x29\xae\xda\x62\x85\xc5\x87\x4b"
+ "\x2a\x3f\xba\xbe\x15\x5e\xb0\x4e\x8e\xe7\x66\xae\xb4\x80\x66\x90"
+ "\x10\x9d\x81\xb9\x64\xd3\x36\x00\xb2\x95\xa8\x7d\xaf\x54\xf8\xbd"
+ "\x8f\x7a\xb1\xa1\xde\x09\x0d\x10\xc8\x8e\x1e\x18\x2c\x1e\x73\x71"
+ "\x2f\x1e\xfd\x16\x6e\xbe\xe1\x3e\xe5\xb4\xb5\xbf\x03\x63\xf4\x5a"
+ "\x0d\xeb\xff\xe0\x61\x80\x67\x51\xb4\xa3\x1f\x18\xa5\xa9\xf1\x9a"
+ "\xeb\x2a\x7f\x56\xb6\x01\x88\x82\x78\xdb\xec\xb7\x92\xfd\xef\x56"
+ "\x55\xd3\x72\x35\xcd\xa4\x0d\x19\x6a\xb6\x79\x91\xd5\xcb\x0e\x3b"
+ "\xfb\xea\xa3\x55\x9f\x77\xfb\x75\xc2\x3e\x09\x02\x73\x7a\xff\x0e"
+ "\xa5\xf0\x83\x11\xeb\xe7\xff\x3b\xd0\xfd\x7a\x07\x53\x63\x43\x89"
+ "\xf5\x7b\xc4\x7d\x3b\x2c\x9b\xca\x1c\xf6\xb2\xab\x13\xf5\xc4\x2a"
+ "\xbf\x46\x77\x3b\x09\xdd\xd1\x80\xef\x55\x11\x3e\xd8\xe4\x42\x22",
+ "\xa3\x86\xa1\x5f\xe3\x4f\x3b\xed\x12\x23\xeb\x5c\xb8\x0c\xad\x4a" },
+ /* After setiv, ctr_low: 0xfffffffc */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x9b\xc8\xc3\xaf",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x33\x5f\xdc\x8d\x5d\x77\x7b\x78\xc1\x5b\x7b\xb3\xd9\x08\x9a\x0c"
+ "\xce\x63\x4e\xef\x19\xf8\x8c\x7a\xcb\x31\x39\x93\x69\x7a\x2c\x97"
+ "\x3a\xb4\x52\x45\x9e\x7b\x78\xbc\xa9\xad\x54\x7f\x88\xa6\xae\xd5"
+ "\xc0\x8b\x7a\xe4\x23\x6b\xb2\x29\x98\xea\x25\x7a\xae\x11\x0c\xc9"
+ "\xf3\x77\xa1\x74\x82\xde\x0c\xec\x68\xce\x94\xfd\xb0\xa0\xc5\x32"
+ "\xd6\xbb\xc3\xe7\xed\x3c\x6f\x0b\x53\x9d\xf3\xc8\xeb\x4e\xee\x99"
+ "\x19\xc7\x16\xd1\xa5\x59\x1d\xa9\xd3\xe6\x43\x52\x74\x61\x28\xe6"
+ "\xac\xd8\x47\x63\xc2\xb7\x53\x39\xc1\x9a\xb0\xa3\xa4\x26\x14\xd0"
+ "\x88\xa9\x8c\xc5\x6d\xe9\x21\x7c\xb9\xa5\xab\x67\xe3\x8d\xe9\x1d"
+ "\xe3\x1c\x7b\xcd\xa4\x12\x0c\xd7\xa6\x5d\x41\xcf\xdd\x3d\xfc\xbc"
+ "\x2a\xbb\xa2\x7a\x9c\x4b\x3a\x42\x6c\x98\x1d\x50\x99\x9c\xfb\xda"
+ "\x21\x09\x2a\x31\xff\x05\xeb\xa5\xf1\xba\x65\x78\xbe\x15\x8e\x84"
+ "\x35\xdd\x45\x29\xcc\xcd\x32\x2d\x27\xe9\xa8\x94\x4b\x16\x16\xcc"
+ "\xab\xf2\xec\xfb\xa0\xb5\x9d\x39\x81\x3e\xec\x5e\x3d\x13\xd1\x83"
+ "\x04\x79\x2d\xbb\x2c\x76\x76\x93\x28\x77\x27\x13\xdd\x1d\x3e\x89"
+ "\x3e\x37\x46\x4c\xb8\x34\xbe\xbf\x9f\x4f\x9f\x37\xff\x0c\xe6\x14"
+ "\x14\x66\x52\x41\x18\xa9\x39\x2b\x0c\xe5\x44\x04\xb0\x93\x06\x64"
+ "\x67\xf7\xa0\x19\xa7\x61\xcf\x03\x7b\xcb\xc8\xb3\x88\x28\xe4\xe7",
+ "\xe6\xe8\x0a\xe3\x72\xfc\xe0\x07\x69\x09\xf2\xeb\xbc\xc8\x6a\xf0" },
+ /* After setiv, ctr_low: 0xfffffffb */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x60\x95\x1a\xe2",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\xd8\x32\x5a\xe3\x55\x8e\xb3\xc2\x51\x84\x2b\x09\x01\x5e\x6c\xfb"
+ "\x4a\xc4\x88\xa0\x33\xe7\x3e\xbf\xe5\x7c\xd2\x00\x4c\x1a\x85\x32"
+ "\x34\xec\x38\x9d\x18\x5f\xf1\x50\x61\x82\xee\xf3\x84\x5a\x84\x4e"
+ "\xeb\x29\x08\x4c\x7b\xb5\x27\xec\x7d\x79\x77\xd7\xa1\x68\x91\x32"
+ "\x2d\xf3\x38\xa9\xd6\x27\x16\xfb\x7d\x8b\x09\x5e\xcf\x1b\x74\x6d"
+ "\xcf\x51\x91\x91\xa1\xe7\x40\x19\x43\x7b\x0d\xa5\xa9\xa5\xf4\x2e"
+ "\x7f\x1c\xc7\xba\xa2\xea\x00\xdd\x24\x01\xa8\x66\x1e\x88\xf1\xf6"
+ "\x0c\x9a\xd6\x2b\xda\x3f\x3e\xb2\x98\xea\x89\xc7\xc6\x63\x27\xb7"
+ "\x6a\x48\x9a\xee\x1e\x70\xa0\xc8\xec\x3d\xc3\x3e\xb5\xf0\xc2\xb1"
+ "\xb9\x71\x1a\x69\x9d\xdd\x72\x1e\xfe\x72\xa0\x21\xb8\x9f\x18\x96"
+ "\x26\xcf\x89\x2e\x92\xf1\x02\x65\xa5\xb4\x2e\xb7\x4e\x12\xbd\xa0"
+ "\x48\xbe\xf6\x5c\xef\x7e\xf3\x0a\xcf\x9d\x1f\x1e\x14\x70\x3e\xa0"
+ "\x01\x0f\x14\xbf\x38\x10\x3a\x3f\x3f\xc2\x76\xe0\xb0\xe0\x7c\xc6"
+ "\x77\x6d\x7f\x69\x8e\xa0\x4b\x00\xc3\x9d\xf9\x0b\x7f\x8a\x8e\xd3"
+ "\x17\x58\x40\xfe\xaf\xf4\x16\x3a\x65\xff\xce\x85\xbb\x80\xfa\xb8"
+ "\x34\xc9\xef\x3a\xdd\x04\x46\xca\x8f\x70\x48\xbc\x1c\x71\x4d\x6a"
+ "\x17\x30\x32\x87\x2e\x2e\x54\x9e\x3f\x15\xed\x17\xd7\xa1\xcf\x6c"
+ "\x5d\x0f\x3c\xee\xf5\x96\xf1\x8f\x68\x1c\xbc\x27\xdc\x10\x3c\x3c",
+ "\x8c\x31\x06\xbb\xf8\x18\x2d\x9d\xd1\x0d\x03\x56\x2b\x28\x25\x9b" },
+ /* After setiv, ctr_low: 0xfffffffa */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x6b\x99\x9b\xda",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x7a\x74\x57\xe7\xc1\xb8\x7e\xcf\x91\x98\xf4\x1a\xa4\xdb\x4d\x2c"
+ "\x6e\xdc\x05\x0b\xd1\x16\xdf\x25\xa8\x1e\x42\xa6\xf9\x09\x36\xfb"
+ "\x02\x8a\x10\x7d\xa1\x07\x88\x40\xb7\x41\xfd\x64\xf6\xe3\x92\x20"
+ "\xfd\xc9\xde\xbd\x88\x46\xd3\x1f\x20\x14\x73\x86\x09\xb6\x68\x61"
+ "\x64\x90\xda\x24\xa8\x0f\x6a\x10\xc5\x01\xbf\x52\x8a\xee\x23\x44"
+ "\xd5\xb0\xd8\x68\x5e\x77\xc3\x62\xed\xcb\x3c\x1b\x0c\x1f\x13\x92"
+ "\x2c\x74\x6d\xee\x40\x1b\x6b\xfe\xbe\x3c\xb8\x02\xdd\x24\x9d\xd3"
+ "\x3d\x4e\xd3\x9b\x18\xfd\xd6\x8f\x95\xef\xa3\xbf\xa9\x2f\x33\xa8"
+ "\xc2\x37\x69\x58\x92\x42\x3a\x30\x46\x12\x1b\x2c\x04\xf0\xbf\xa9"
+ "\x79\x55\xcd\xac\x45\x36\x79\xc0\xb4\xb2\x5f\x82\x88\x49\xe8\xa3"
+ "\xbf\x33\x41\x7a\xcb\xc4\x11\x0e\xcc\x61\xed\xd1\x6b\x59\x5f\x9d"
+ "\x20\x6f\x85\x01\xd0\x16\x2a\x51\x1b\x79\x35\x42\x5e\x49\xdf\x6f"
+ "\x64\x68\x31\xac\x49\x34\xfb\x2b\xbd\xb1\xd9\x12\x4e\x4b\x16\xc5"
+ "\xa6\xfe\x15\xd3\xaf\xac\x51\x08\x95\x1f\x8c\xd2\x52\x37\x8b\x88"
+ "\xf3\x20\xe2\xf7\x09\x55\x82\x83\x1c\x38\x5f\x17\xfc\x37\x26\x21"
+ "\xb8\xf1\xfe\xa9\xac\x54\x1e\x53\x83\x53\x3f\x43\xe4\x67\x22\xd5"
+ "\x86\xec\xf2\xb6\x4a\x8b\x8a\x66\xea\xe0\x92\x50\x3b\x51\xe4\x00"
+ "\x25\x2a\x7a\x64\x14\xd6\x09\xe1\x6c\x75\x32\x28\x53\x5e\xb3\xab",
+ "\x5d\x4b\xb2\x8f\xfe\xa5\x7f\x01\x6d\x78\x6c\x13\x58\x08\xe4\x94" },
+ /* After setiv, ctr_low: 0xfffffff9 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x90\xc4\x42\x97",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\xf5\xc1\xed\xb8\x7f\x55\x7b\xb5\x47\xed\xaa\x42\xd2\xda\x33\x41"
+ "\x4a\xe0\x36\x6d\x51\x28\x40\x9c\x35\xfb\x11\x65\x18\x83\x9c\xb5"
+ "\x02\xb2\xa7\xe5\x52\x27\xa4\xe8\x57\x3d\xb3\xf5\xea\xcb\x21\x07"
+ "\x67\xbe\xbe\x0f\xf6\xaa\x32\xa1\x4b\x5e\x79\x4f\x50\x67\xcd\x80"
+ "\xfc\xf1\x65\xf2\x6c\xd0\xdb\x17\xcc\xf9\x52\x93\xfd\x5e\xa6\xb9"
+ "\x5c\x9f\xa8\xc6\x36\xb7\x80\x80\x6a\xea\x62\xdc\x61\x13\x45\xbe"
+ "\xab\x8f\xd8\x99\x17\x51\x9b\x29\x04\x6e\xdb\x3e\x9f\x83\xc6\x35"
+ "\xb3\x90\xce\xcc\x74\xec\xcb\x04\x41\xac\xb1\x92\xde\x20\xb1\x67"
+ "\xb0\x38\x14\xaa\x7d\xee\x3c\xb2\xd3\xbb\x2f\x88\x0b\x73\xcf\x7b"
+ "\x69\xc1\x55\x5b\x2b\xf2\xd4\x38\x2b\x3c\xef\x04\xc9\x14\x7c\x31"
+ "\xd6\x61\x88\xa8\xb3\x8c\x69\xb4\xbc\xaa\x0d\x15\xd2\xd5\x27\x63"
+ "\xc4\xa4\x80\xe9\x2b\xe9\xd2\x34\xc9\x0e\x3f\x7b\xd3\x43\x0d\x47"
+ "\x5d\x37\x8e\x42\xa4\x4e\xef\xcd\xbb\x3a\x5b\xa4\xe1\xb0\x8d\x64"
+ "\xb7\x0b\x58\x52\xec\x55\xd0\xef\x23\xfe\xf2\x8d\xe0\xd1\x6a\x2c"
+ "\xaa\x1c\x03\xc7\x3e\x58\x4c\x61\x72\x07\xc6\xfd\x0e\xbc\xd4\x6b"
+ "\x99\x4f\x91\xda\xff\x6f\xea\x81\x0c\x76\x85\x5d\x0c\x7f\x1c\xb8"
+ "\x84\x8c\x2f\xe1\x36\x3e\x68\xa0\x57\xf5\xdf\x13\x0a\xd6\xe1\xcd"
+ "\xae\x23\x99\x4e\xed\x7a\x72\x1b\x7c\xe5\x65\xd1\xb7\xcf\x2f\x73",
+ "\x1e\x2f\xcf\x3c\x95\x9a\x29\xec\xd3\x37\x90\x8c\x84\x8a\xfb\x95" },
+ /* After setiv, ctr_low: 0xfffffff8 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xb7\xfa\xc7\x4f",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x14\x33\xc6\x9d\x04\xd3\x48\x29\x0c\x6a\x24\x27\xdf\x5f\x0a\xd2"
+ "\x71\xd6\xd0\x18\x04\xc0\x9f\x72\x0a\x60\xb7\x10\x52\x56\xf7\xae"
+ "\x64\xb0\x28\xd4\xfd\x25\x93\x8e\x67\x7e\xac\xc2\x93\xc7\x54\x2e"
+ "\x82\x93\x88\x6a\xb9\x8b\x73\xbc\x88\xec\x27\xdd\x4f\x9b\x21\x9e"
+ "\x77\x98\x70\x0b\xf4\xd8\x55\xfe\xf4\xc3\x3a\xcb\xca\x3a\xfb\xd4"
+ "\x52\x72\x2f\xf8\xac\xa9\x6a\xf5\x13\xab\x7a\x2e\x9f\x52\x41\xbd"
+ "\x87\x90\x68\xad\x17\xbd\x5a\xff\xc3\xc6\x10\x4d\xc1\xfe\xfc\x72"
+ "\x21\xb5\x53\x4a\x3f\xe0\x15\x9f\x29\x36\x23\xc0\x9a\x31\xb2\x0f"
+ "\xcd\x2f\xa6\xd0\xfc\xe6\x4d\xed\x68\xb3\x3d\x26\x67\xab\x40\xf0"
+ "\xab\xcf\x72\xc0\x50\xb1\x1e\x86\x38\xe2\xe0\x46\x3a\x2e\x3e\x1d"
+ "\x07\xd6\x9d\xe8\xfc\xa3\xe7\xac\xc9\xa0\xb3\x22\x05\xbc\xbf\xd2"
+ "\x63\x44\x66\xfc\xb4\x7b\xb4\x70\x7e\x96\xa9\x16\x1b\xb2\x7d\x93"
+ "\x44\x92\x5e\xbd\x16\x34\xa7\x11\xd0\xdf\x52\xad\x6f\xbd\x23\x3c"
+ "\x3d\x58\x16\xaf\x99\x8b\xbb\xa0\xdc\x3a\xff\x17\xda\x56\xba\x77"
+ "\xae\xc4\xb1\x51\xe2\x61\x4f\xf0\x66\x1b\x4c\xac\x79\x34\x1c\xfd"
+ "\x6c\x5f\x9a\x2c\x60\xfc\x47\x00\x5f\x2d\x81\xcc\xa9\xdd\x2b\xf4"
+ "\x5b\x53\x44\x61\xd4\x13\x5a\xf3\x93\xf0\xc9\x24\xd4\xe6\x60\x6f"
+ "\x78\x02\x0c\x75\x9d\x0d\x23\x97\x35\xe2\x06\x8a\x49\x5e\xe5\xbe",
+ "\x23\xc0\x4a\x2f\x98\x93\xca\xbd\x2e\x44\xde\x05\xcc\xe7\xf1\xf5" },
+ /* After setiv, ctr_low: 0xfffffff7 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x4c\xa7\x1e\x02",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x51\x51\x64\x89\xeb\x9f\xf9\xd6\xb1\xa6\x73\x5f\xf1\x62\xb5\xe4"
+ "\x00\x80\xdb\x4c\x1c\xce\xe5\x00\xeb\xea\x6c\x57\xe4\x27\xfc\x71"
+ "\x08\x8c\xa1\xfc\x59\x1d\x07\x45\x3c\xc9\x4e\x0f\xb6\xea\x96\x90"
+ "\xae\xf7\x81\x1e\x7e\x6c\x5e\x50\xaf\x34\x3e\xa0\x55\x59\x8e\xe7"
+ "\xc1\xba\x48\xfa\x9e\x07\xf6\x6a\x24\x54\x3e\x9b\xa5\xfe\x31\x16"
+ "\x3d\x4d\x9c\xc4\xe1\xec\x26\xa0\x8b\x59\xa6\xf3\x94\xf8\x88\xda"
+ "\x1f\x88\x23\x5f\xfb\xfd\x79\xa2\xd3\x62\x30\x66\x69\xd9\x0d\x05"
+ "\xc0\x75\x4c\xb8\x48\x34\x1d\x97\xcf\x29\x6a\x12\x1c\x26\x54\x1d"
+ "\x80\xa9\x06\x74\x86\xff\xc6\xb4\x72\xee\x34\xe2\x56\x06\x6c\xf5"
+ "\x11\xe7\x26\x71\x47\x6b\x05\xbd\xe4\x0b\x40\x78\x84\x3c\xf9\xf2"
+ "\x78\x34\x2b\x3c\x5f\x0e\x4c\xfb\x17\x39\xdc\x59\x6b\xd1\x56\xac"
+ "\xe4\x1f\xb9\x19\xbc\xec\xb1\xd0\x6d\x47\x3b\x37\x4d\x0d\x6b\x65"
+ "\x7c\x70\xe9\xec\x58\xcc\x09\xd4\xd9\xbf\x9f\xe0\x6c\x7f\x60\x28"
+ "\xd8\xdf\x8e\xd1\x6a\x73\x42\xf3\x50\x01\x79\x68\x41\xc3\xba\x19"
+ "\x1e\x2d\x30\xc2\x81\x2c\x9f\x11\x8b\xd0\xdc\x31\x3b\x01\xfe\x53"
+ "\xa5\x11\x13\x22\x89\x40\xb9\x1b\x12\x89\xef\x9a\xcb\xa8\x03\x4f"
+ "\x54\x1a\x15\x6d\x11\xba\x05\x09\xd3\xdb\xbf\x05\x42\x3a\x5a\x27"
+ "\x3b\x34\x5c\x58\x8a\x5c\xa4\xc2\x28\xdc\xb2\x3a\xe9\x99\x01\xd6",
+ "\x30\xb2\xb5\x11\x8a\x3a\x8d\x70\x67\x71\x14\xde\xed\xa7\x43\xb5" },
+ /* After setiv, ctr_low: 0xfffffff6 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x47\xab\x9f\x3a",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x05\x72\x44\xa0\x99\x11\x1d\x2c\x4b\x03\x4f\x20\x92\x88\xbe\x55"
+ "\xee\x31\x2c\xd9\xc0\xc1\x64\x77\x79\xd7\x3e\xfa\x5a\x7d\xf0\x48"
+ "\xf8\xc8\xfe\x81\x8f\x89\x92\xa6\xc2\x07\xdc\x9f\x3f\xb2\xc8\xf2"
+ "\xf3\xe9\xe1\xd3\xed\x55\xb4\xab\xc3\x22\xed\x8f\x00\xde\x32\x95"
+ "\x91\xc0\xc5\xf3\xd3\x93\xf0\xee\x56\x14\x8f\x96\xff\xd0\x6a\xbd"
+ "\xfc\x57\xc2\xc3\x7b\xc1\x1d\x56\x48\x3f\xa6\xc7\x92\x47\xf7\x2f"
+ "\x0b\x85\x1c\xff\x87\x29\xe1\xbb\x9b\x14\x6c\xac\x51\x0a\xc0\x7b"
+ "\x22\x25\xb0\x48\x92\xad\x09\x09\x6e\x39\x8e\x96\x13\x05\x55\x92"
+ "\xbd\xd7\x5d\x95\x35\xdd\x8a\x9d\x05\x59\x60\xae\xbb\xc0\x85\x92"
+ "\x4c\x8b\xa0\x3f\xa2\x4a\xe5\x2e\xde\x85\x1a\x39\x10\x22\x11\x1b"
+ "\xdd\xcc\x96\xf4\x93\x97\xf5\x81\x85\xf3\x33\xda\xa1\x9a\xba\xfd"
+ "\xb8\xaf\x60\x81\x37\xf1\x02\x88\x54\x15\xeb\x21\xd1\x19\x1a\x1f"
+ "\x28\x9f\x02\x27\xca\xce\x97\xda\xdc\xd2\x0f\xc5\x0e\x2e\xdd\x4f"
+ "\x1d\x24\x62\xe4\x6e\x4a\xbe\x96\x95\x38\x0c\xe9\x26\x14\xf3\xf0"
+ "\x92\xbc\x97\xdc\x38\xeb\x64\xc3\x04\xc1\xa2\x6c\xad\xbd\xf8\x03"
+ "\xa0\xa4\x68\xaa\x9d\x1f\x09\xe6\x62\x95\xa2\x1c\x32\xef\x62\x28"
+ "\x7e\x54\x6d\x4b\x6a\xcc\x4a\xd0\x82\x47\x46\x0d\x45\x3c\x36\x03"
+ "\x86\x90\x44\x65\x18\xac\x19\x75\xe6\xba\xb1\x9a\xb4\x5d\x84\x9b",
+ "\x31\x22\x2b\x11\x6e\x2b\x94\x56\x37\x9d\xc3\xa5\xde\xe7\x6e\xc9" },
+ /* After setiv, ctr_low: 0xfffffff5 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xbc\xf6\x46\x77",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x6e\x32\xdb\x04\x32\x57\x15\x78\x0e\x4c\x70\x66\x5c\x91\x43\x0c"
+ "\x63\x73\xb8\x86\xad\xb0\xf1\x34\x0f\x0c\x7e\xd3\x4e\xcb\xc9\xea"
+ "\x19\x3c\xb8\x14\xd0\xab\x9e\x9b\x22\xda\x7a\x96\xa7\xf5\xa2\x99"
+ "\x58\xe3\xd6\x72\x0f\xf5\xdf\x88\xd1\x33\xb1\xe5\x03\x72\x62\x1c"
+ "\xa7\xf2\x67\x50\x0e\x70\xc3\x7a\x6c\x4a\x90\xba\x78\x9e\xd2\x0b"
+ "\x29\xd4\xc8\xa7\x57\x06\xf2\xf4\x01\x4b\x30\x53\xea\xf7\xde\xbf"
+ "\x1c\x12\x03\xcf\x9f\xcf\x80\x8b\x77\xfd\x73\x48\x79\x19\xbe\x38"
+ "\x75\x0b\x6d\x78\x7d\x79\x05\x98\x65\x3b\x35\x8f\x68\xff\x30\x7a"
+ "\x6e\xf7\x10\x9e\x11\x25\xc4\x95\x97\x7d\x92\x0f\xbf\x38\x95\xbd"
+ "\x5d\x2a\xf2\x06\x2c\xd9\x5a\x80\x91\x4e\x22\x7d\x5f\x69\x85\x03"
+ "\xa7\x5d\xda\x22\x09\x2b\x8d\x29\x67\x7c\x8c\xf6\xb6\x49\x20\x63"
+ "\xb9\xb6\x4d\xb6\x37\xa3\x7b\x19\xa4\x28\x90\x83\x55\x3d\x4e\x18"
+ "\xc8\x65\xbc\xd1\xe7\xb5\xcf\x65\x28\xea\x19\x11\x5c\xea\x83\x8c"
+ "\x44\x1f\xac\xc5\xf5\x3a\x4b\x1c\x2b\xbf\x76\xd8\x98\xdb\x50\xeb"
+ "\x64\x45\xae\xa5\x39\xb7\xc8\xdf\x5a\x73\x6d\x2d\x0f\x4a\x5a\x17"
+ "\x37\x66\x1c\x3d\x27\xd5\xd6\x7d\xe1\x08\x7f\xba\x4d\x43\xc2\x29"
+ "\xf7\xbe\x83\xec\xd0\x3b\x2e\x19\x9e\xf7\xbf\x1b\x16\x34\xd8\xfa"
+ "\x32\x17\x2a\x90\x55\x93\xd5\x3e\x14\x8d\xd6\xa1\x40\x45\x09\x52",
+ "\x89\xf2\xae\x78\x38\x8e\xf2\xd2\x52\xa8\xba\xb6\xf2\x5d\x7c\xfc" },
+ /* After setiv, ctr_low: 0xfffffff4 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x51\xb2\x9d\x4a",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x1d\xb8\x77\xcd\xcd\xfe\xde\x07\x97\xcb\x97\x3a\x4f\xa0\xd0\xe6"
+ "\xcc\xcf\x8b\x71\xd5\x65\x3d\xc4\x17\x52\xe7\x1d\x6a\x68\x4a\x77"
+ "\xca\x04\x4a\xef\x8e\x7e\xce\x79\xa1\x80\x0d\x9e\xd5\xf4\xce\x66"
+ "\x4d\x54\xb1\x09\xd1\xb6\xb0\x43\x28\xe8\x53\xe2\x24\x9c\x76\xc5"
+ "\x4d\x22\xf3\x6e\x13\xf3\xd7\xe0\x85\xb8\x9e\x0b\x17\x22\xc0\x79"
+ "\x2b\x72\x57\xaa\xbd\x43\xc3\xf7\xde\xce\x22\x41\x3c\x7e\x37\x1a"
+ "\x55\x2e\x36\x0e\x7e\xdc\xb3\xde\xd7\x33\x36\xc9\xc8\x56\x93\x51"
+ "\x68\x77\x9a\xb0\x08\x5c\x22\x35\xef\x5c\x9b\xbf\x3e\x20\x8a\x84"
+ "\x3d\xb3\x60\x10\xe1\x97\x30\xd7\xb3\x6f\x40\x5a\x2c\xe0\xe5\x52"
+ "\x19\xb6\x2b\xed\x6e\x8e\x18\xb4\x8d\x78\xbd\xc4\x9f\x4f\xbd\x82"
+ "\x98\xd6\x71\x3d\x71\x5b\x78\x73\xee\x8e\x4b\x37\x88\x9e\x21\xca"
+ "\x00\x6c\xc2\x96\x8d\xf0\xcd\x09\x58\x54\x5a\x58\x59\x8e\x9b\xf8"
+ "\x72\x93\xd7\xa0\xf9\xc4\xdc\x48\x89\xaa\x31\x95\xda\x4e\x2f\x79"
+ "\x1e\x37\x49\x92\x2e\x32\x2e\x76\x54\x2a\x64\xa8\x96\x67\xe9\x75"
+ "\x10\xa6\xeb\xad\xc6\xa8\xec\xb7\x18\x0a\x32\x26\x8d\x6e\x03\x74"
+ "\x0e\x1f\xfc\xde\x76\xff\x6e\x96\x42\x2d\x80\x0a\xc6\x78\x70\xc4"
+ "\xd8\x56\x7b\xa6\x38\x2f\xf6\xc0\x9b\xd7\x21\x6e\x88\x5d\xc8\xe5"
+ "\x02\x6a\x09\x1e\xb3\x46\x44\x80\x82\x5b\xd1\x66\x06\x61\x4f\xb8",
+ "\x16\x0e\x73\xa3\x14\x43\xdb\x15\x9c\xb0\x0d\x30\x6d\x9b\xe1\xb1" },
+ /* After setiv, ctr_low: 0xfffffff3 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xaa\xef\x44\x07",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x42\x71\x54\xe2\xdb\x50\x5d\x3c\x10\xbd\xf8\x60\xbd\xdb\x26\x14"
+ "\x7d\x13\x59\x98\x28\xfb\x43\x42\xca\x72\xe6\xd8\x58\x00\xa2\x1b"
+ "\x6a\x61\xb4\x3a\x80\x6b\x9e\x14\xbd\x11\x33\xab\xe9\xb9\x91\x95"
+ "\xd7\x5d\xc3\x98\x1f\x7f\xcb\xa8\xf0\xec\x31\x26\x51\xea\x2e\xdf"
+ "\xd9\xde\x70\xf5\x84\x27\x3a\xac\x22\x05\xb9\xce\x2a\xfb\x2a\x83"
+ "\x1e\xce\x0e\xb2\x31\x35\xc6\xe6\xc0\xd7\xb0\x5f\xf5\xca\xdb\x13"
+ "\xa7\xfe\x4f\x85\xa3\x4f\x94\x5c\xc1\x04\x12\xde\x6f\xa1\xdb\x41"
+ "\x59\x82\x22\x22\x65\x97\x6d\xc8\x67\xab\xf3\x90\xeb\xa4\x00\xb3"
+ "\x7d\x94\x3d\x7b\x2a\xe2\x85\x36\x87\x16\xb8\x19\x92\x02\xe0\x43"
+ "\x42\x85\xa1\xe6\xb8\x11\x30\xcc\x2c\xd8\x63\x09\x0e\x53\x5f\xa3"
+ "\xe0\xd4\xee\x0e\x04\xee\x65\x61\x96\x84\x42\x0c\x68\x8d\xb7\x48"
+ "\xa3\x02\xb4\x82\x69\xf2\x35\xe4\xce\x3b\xe3\x44\xce\xad\x49\x32"
+ "\xab\xda\x04\xea\x06\x60\xa6\x2a\x7d\xee\x0f\xb8\x95\x90\x22\x62"
+ "\x9c\x78\x59\xd3\x7b\x61\x02\x65\x63\x96\x9f\x67\x50\xa0\x61\x43"
+ "\x53\xb2\x3f\x22\xed\x8c\x42\x39\x97\xd9\xbc\x6e\x81\xb9\x21\x97"
+ "\xc6\x5b\x68\xd7\x7f\xd0\xc5\x4a\xfb\x74\xc4\xfd\x9a\x2a\xb8\x9b"
+ "\x48\xe0\x00\xea\x6d\xf5\x30\x26\x61\x8f\xa5\x45\x70\xc9\x3a\xea"
+ "\x6d\x19\x11\x57\x0f\x21\xe6\x0a\x53\x94\xe3\x0c\x99\xb0\x2f\xc5",
+ "\x92\x92\x89\xcd\x4f\x3c\x6d\xbc\xe8\xb3\x70\x14\x5b\x3c\x12\xe4" },
+ /* After setiv, ctr_low: 0xfffffff2 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xa1\xe3\xc5\x3f",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\x41\xc3\xcb\xd7\x6e\xde\x2a\xc6\x15\x05\xc6\xba\x27\xae\xcd\x37"
+ "\xc0\xe5\xbf\xb9\x5c\xdc\xd6\xad\x1a\xe1\x35\x7c\xc0\x85\x85\x51"
+ "\x8c\x98\x06\xc0\x72\x43\x71\x7a\x2d\x7c\x81\x3c\xe7\xd6\x32\x8e"
+ "\x22\x2b\x46\x95\x6a\xde\x45\x40\x56\xe9\x63\x32\x68\xbf\xb6\x78"
+ "\xb7\x86\x00\x9d\x2c\x9e\xed\x67\xc1\x9b\x09\x9e\xd9\x0a\x56\xcb"
+ "\x57\xc9\x48\x14\x23\x4e\x97\x04\xb5\x85\x25\x1d\xcb\x1a\x79\x9b"
+ "\x54\x06\x95\xad\x16\x81\x84\x3a\x38\xec\x41\x90\x2a\xfa\x50\xe0"
+ "\xb9\x20\xa6\xeb\xfe\x2e\x5c\xa1\xf6\x3c\x69\x4c\xce\xf8\x30\xe0"
+ "\x87\x68\xa2\x3a\x9d\xad\x75\xd4\xa5\x6b\x0a\x90\x65\xa2\x27\x64"
+ "\x9d\xf5\xa0\x6f\xd0\xd3\x62\xa5\x2d\xae\x02\x89\xb4\x1a\xfa\x32"
+ "\x9b\xa0\x44\xdd\x50\xde\xaf\x41\xa9\x89\x1e\xb0\x41\xbc\x9c\x41"
+ "\xb0\x35\x5e\xf1\x9a\xd9\xab\x57\x53\x21\xca\x39\xfc\x8b\xb4\xd4"
+ "\xb2\x19\x8a\xe9\xb2\x24\x1e\xce\x2e\x19\xb0\xd2\x93\x30\xc4\x70"
+ "\xe2\xf8\x6a\x8a\x99\x3b\xed\x71\x7e\x9e\x98\x99\x2a\xc6\xdd\xcf"
+ "\x43\x32\xdb\xfb\x27\x22\x89\xa4\xc5\xe0\xa2\x94\xe9\xcf\x9d\x48"
+ "\xab\x3f\xfa\x4f\x75\x63\x46\xdd\xfe\xfa\xf0\xbf\x6e\xa1\xf9\xca"
+ "\xb1\x77\x79\x35\x6c\x33\xe1\x57\x68\x50\xe9\x78\x4e\xe4\xe2\xf0"
+ "\xcf\xe4\x23\xde\xf4\xa7\x34\xb3\x44\x97\x38\xd2\xbd\x27\x44\x0e",
+ "\x75\x0a\x41\x3b\x87\xe3\xc7\xf6\xd6\xe3\xab\xfa\x4b\xbe\x2e\x56" },
+ /* After setiv, ctr_low: 0xfffffff1 */
+ { GCRY_CIPHER_AES256,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x5a\xbe\x1c\x72",
+ 16,
+ "", 0,
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+ 288,
+ "\xf1\x3c\x7a\xa4\xa9\xaf\xe7\x49\x19\x7d\xad\x50\xc1\x6a\x84\x87"
+ "\xf5\x69\xe4\xe5\xc2\x0a\x90\x33\xc3\xeb\x76\x63\x5f\x9b\x1d\xf9"
+ "\x53\x4a\x2a\x6d\x6b\x61\xe0\x5d\xed\xcb\x98\x0d\xf2\x57\x33\x12"
+ "\xd1\x44\xaa\x7a\x7e\x4e\x41\x0e\xe6\xa7\x9f\x17\x92\x28\x91\xad"
+ "\xca\xce\xf2\xa8\x73\x4a\xad\x89\x62\x73\x0b\x9a\x68\x91\xa8\x11"
+ "\x44\x01\xfd\x57\xe4\xf8\x84\x55\x2b\x66\xdb\xb9\xd6\xee\x83\xe5"
+ "\x57\xea\x5c\x6a\x23\x87\xdd\x0a\x45\x63\xb4\x0c\x8f\xc5\x9f\x22"
+ "\xf3\x4f\x4e\x6f\x7b\x14\x62\xf7\x80\x59\x4a\xc5\xc8\xae\x8a\x6f"
+ "\x5e\xe3\x1e\xe6\xae\xec\x99\x77\x6b\x88\x14\xe3\x58\x88\x61\x74"
+ "\x38\x91\xa1\x32\xb8\xd2\x39\x6b\xe2\xcb\x8e\x77\xde\x92\x36\x78"
+ "\xad\x50\xcf\x08\xb8\xfa\x29\x59\xb4\x68\x1b\x23\x10\x57\x32\x92"
+ "\xf8\xec\xe1\x97\xdb\x30\x85\x22\xb5\x68\x2f\xf2\x98\xda\x06\xee"
+ "\x65\x02\xe7\xf9\xc8\xc1\xca\x8f\xd3\xed\x4a\x3c\x09\xdd\xde\x64"
+ "\xd9\x85\x17\x2c\x62\x41\x35\x24\xed\x6b\x87\x78\x1e\xb5\x7a\x9b"
+ "\xa3\x90\xa3\x99\xc7\x39\x51\x10\xb7\x6a\x12\x3b\x64\xfe\x32\x3c"
+ "\xb6\x84\x9a\x3f\x95\xd3\xcb\x22\x69\x9c\xf9\xb7\xc2\x8b\xf4\x55"
+ "\x68\x60\x11\x20\xc5\x3e\x0a\xc0\xba\x00\x0e\x88\x96\x66\xfa\xf0"
+ "\x75\xbc\x2b\x9c\xff\xc5\x33\x7b\xaf\xb2\xa6\x34\x78\x44\x9c\xa7",
+ "\x01\x24\x0e\x17\x17\xe5\xfc\x90\x07\xfa\x78\xd5\x5d\x66\xa3\xf5" },
};
gcry_cipher_hd_t hde, hdd;
- unsigned char out[MAX_DATA_LEN];
+ unsigned char out[MAX_GCM_DATA_LEN];
unsigned char tag[GCRY_GCM_BLOCK_LEN];
int i, keylen;
gcry_error_t err = 0;
_check_gcm_cipher(1);
/* Split input to 7 byte buffers. */
_check_gcm_cipher(7);
+ /* Split input to 15 byte buffers. */
+ _check_gcm_cipher(15);
/* Split input to 16 byte buffers. */
_check_gcm_cipher(16);
+ /* Split input to 17 byte buffers. */
+ _check_gcm_cipher(17);
}
}
+/* Check the point on curve function. */
+static void
+point_on_curve (void)
+{
+ static struct {
+ const char *curve;
+ int oncurve; /* Point below is on the curve. */
+ const char *qx;
+ const char *qy;
+ } t[] = {
+ {
+ "NIST P-256", 0,
+ "015B4F6775D68D4D2E2192C6B8027FC5A3D49957E453CB251155AA3FF5D3EC9974",
+ "4BC4C87B57A25E1056831208AB5B8F091142F891E9FF19F1E090B030DF1087B3"
+ }, {
+ "NIST P-256", 0,
+ "D22C316E7EBE7B293BD66808E000806F0754398A5D72A4F9BBC21C26EAC0A651",
+ "3C8DB80CC3CDE5E530D040536E6A58AAB41C33FA70B30896943513FF3690132D"
+ }, {
+ "NIST P-256", 0,
+ "0130F7E7BC52854CA493A0DE87DC4AB3B4343758F2B634F15B10D70DBC0A5A5291",
+ "86F9CA73C25CE86D54CB21C181AECBB52A5971334FF5040F76CAE9845ED46023"
+ }, {
+ "NIST P-256", 1,
+ "14957B602C7849F28858C7407696F014BC091D6D68C449560B7A38147D6E6A9B",
+ "A8E09EFEECFE00C797A0848F38B61992D30C61FAB13021E88C8BD3545B3A6C63"
+ }, {
+ "NIST P-256", 0,
+ "923DE4957241DD97780841C76294DB0D4F5DC04C3045081174764D2D32AD2D53",
+ "01B4B1A2027C02F0F520A3B01E4CE3C668BF481346A74499C5D1044A53E210B600"
+ }, {
+ "NIST P-256", 1,
+ "9021DFAB8B4DAEAADA634AAA26D6E5FFDF8C0476FF5CA31606C870A1B933FB36",
+ "9AFC65EEB24E46C7B75712EF29A981CB09FAC56E2B81D3ED024748CCAB1CB77E"
+ }, {
+ "NIST P-256", 0,
+ "011529F0B26DE5E0EB2DA4BFB6C149C802CB52EE479DD666553286928A4005E990",
+ "0EBC63DB2104884456DC0AA81A3F4E99D93B7AE2CD4B1489655EA9BE6289CF9E"
+ }, {
+ "NIST P-256", 1,
+ "216EC5DE8CA989199D31F0DFCD381DCC9270A0785365EC3E34CA347C070A87BE",
+ "87A88897BA763509ECC1DBE28D9D37F6F4E70E3B99B1CD3C0B934D4190968A6D"
+ }, {
+ "NIST P-256", 1,
+ "7ABAA44ACBC6016FDB52A6F45F6178E65CBFC35F9920D99149CA9999612CE945",
+ "88F7684BDCDA31EAFB6CAD859F8AB29B5D921D7DB2B34DF7E40CE36235F45B63"
+ }, {
+ "NIST P-256", 0,
+ "E765B4272D211DD0064189B55421FB76BB3A7756364A6CB1627FAED848157A84",
+ "C13171CFFB243E06B203F0996BBDD16F52292AD11F2DA81106E9C2FD87F4FA0F"
+ }, {
+ "NIST P-256", 0,
+ "EE4999DFC3A1871EE7A592BE26A09BEC9D9B561613EE9EFB6ED42F17985C9CDC",
+ "8399E967338A7A618336AF70DA67D9CAC1C19267809652F5C5183C8B129E0902"
+ }, {
+ "NIST P-256", 0,
+ "F755D0CF2642A2C7FBACCC8E9E442B8B047A99C6E052B2FA5AB0544B36B4D51C",
+ "AA080F17657B6565D9A4D94BD260B54D92FEE8DC4A78C4FC9C19209933AF39B0"
+ } , {
+ "NIST P-384", 0,
+ "CBFC7DBEBF15BEAD682549757F9BBA0E3F67669DF13FCE0EBE8024B725B38B00"
+ "83EC46A8F2FF3203C5C7F8C7E722A5EF",
+ "0548FE281BEAB18FD1AB86F59B0CA524479A4A81373C83B78AFFD801FAC75922"
+ "96470753DCF46173C9AA4A8A4C2FBE51"
+ }, {
+ "NIST P-384", 0,
+ "1DC8E054A883DB81EAEDE6C487B26816C927B8196780525A6CA8F675D2557752"
+ "02CE06CCBE705EA8A38AA2894D4BEEE6",
+ "010191050E867AFAA96A199FE9C591CF8B853D81486786DA889124881FB39D2F"
+ "8E0875F4C4BB1E3D0F8535C7A52306FB82"
+ }, {
+ "NIST P-384", 1,
+ "2539FC368CE1D5E464B6C0FBB12D557B712327DB086975255AD7D17F7E7E4F23"
+ "D719ED4116E2CC907AEB92CF22331A60",
+ "8843FDBA742CB64323E49CEBE8DD74908CFC9C3AA0015662DFBB7219E92CF32E"
+ "9FC63F61EF19DE9B3CEA98D163ABF254"
+ }, {
+ "NIST P-384", 0,
+ "0B786DACF400D43575394349EDD9F9CD145FC7EF737A3C5F69B253BE7639DB24"
+ "EC2F0CA62FF1F90B6515DE356EC2A404",
+ "225D6B2939CC7F7133F43353946A682C68DAC6BB75EE9CF6BD9A1609FA915692"
+ "72F4D3A87E88529754E109BB9B61B03B"
+ }, {
+ "NIST P-384", 0,
+ "76C660C9F58CF2051F9F8B06049694AB6FE418009DE6F0A0833BC690CEC06CC2"
+ "9A440AD51C94CF5BC28817C8C6E2D302",
+ "012974E5D9E55304ED294AB6C7A3C65B663E67ABC5E6F6C0F6498B519F2F6CA1"
+ "8306976291F3ADC0B5ABA42DED376EA9A5"
+ }, {
+ "NIST P-384", 0,
+ "23D758B1EDB8E12E9E707C53C131A19D9464B20EE05C99766F5ABDF9F906AD03"
+ "B958BF28B022E54E320672C4BAD4EEC0",
+ "01E9E72870C88F4C82A5AB3CC8A3398E8F006BF3EC05FFBB1EFF8AEE88020FEA"
+ "9E558E9F58ED1D324C9DCBCB4E8F2A5970"
+ }, {
+ "NIST P-384", 0,
+ "D062B96D5A10F715ACF361F99262ABF0F7693A8BB60ECB1DF459CF95750E4293"
+ "18BCB9FC60499D009F949298F3F9F47B",
+ "9089C6328E4B39A73D7EE6FAE1A77E48CE354B83BBCE432082C32C8FD6784B86"
+ "CFE9C552E2E720F5DA5806503D3784CD"
+ }, {
+ "NIST P-384", 0,
+ "2A951D4D6EB35C43D94866280D37365B82441BC84D62CBFF3365CAB1FD0A3E20"
+ "823CA8F84D2BBF4EA687885437DE7839",
+ "01CC7D762AFE613F7B5568BC516568A421159C40599E8D52DE10E8F9488931E1"
+ "69F3656C322DE45C4A70DC6DB9A661E599"
+ }, {
+ "NIST P-384", 1,
+ "A4BAEE6CDAF3AEB69032B3FBA811707C54F5753670DA5173D891547E8CBAEEF3"
+ "89B92C9A55573A596123415FBFA26991",
+ "3241EA716583C11C71BB30AF6C5E3A6637956F17ADBBE641BAB52E8539F9FC7B"
+ "F3B04F46DBFFE08151E0F0950CC70081"
+ }, {
+ "NIST P-384", 0,
+ "5C0E18B0DE3261BCBCFC7B702C2D75CF481336BFBADF420BADC616235C1966AB"
+ "4C0F876575DDEC1BDB3F3F04061C9AE4",
+ "E90C78550D1C922F1D8161D8C9C0576E29BD09CA665376FA887D13FA8DF48352"
+ "D7BBEEFB803F6CC8FC7895E47F348D33"
+ }, {
+ "NIST P-384", 1,
+ "2015864CD50F0A1A50E6401F44191665C19E4AD4B4903EA9EB464E95D1070E36"
+ "F1D8325E45734D5A0FDD103F4DF6F83E",
+ "5FB3E9A5C59DD5C5262A8176CB7032A00AE33AED08485884A3E5D68D9EEB990B"
+ "F26E8D87EC175577E782AD51A6A12C02"
+ }, {
+ "NIST P-384", 1,
+ "56EBF5310EEF5A5D8D001F570A18625383ECD4882B3FC738A69874E7C9D8F89C"
+ "187BECA23369DFD6C15CC0DA0629958F",
+ "C1230B349FB662CB762563DB8F9FCB32D5CCA16120681C474D67D279CCA6F6DB"
+ "73DE6AA96140B5C457B7486E06D318CE"
+ }, {
+ "NIST P-521", 0,
+ "01E4D82EE5CD6DA37080252295EFA273BBBA6952012D0120EAF131E73F1E5024"
+ "36E3324624471040030E1C345D65490ECEE9B64E03B15B6C7EB69A39C618BAFEED70",
+ "03EE3A3C88A6933B7B16016BE4CC4E3BF5EA0625CB3DB2604CDCBBD02CABBC90"
+ "8904D9DB42998F6C5101D4D4318ACFC9643C9CD641F636D1810ED86F1840EA74F3C0"
+ }, {
+ "NIST P-521", 0,
+ "01F3DFCB5433387B6B2E3F74177F4F3D7300F05E1AD49DE112630E27B1C8A437"
+ "1E742CB020E0039B5477FC897D17332034F9660B3066764EFF5FB440EB8856E782E3",
+ "02D337616C9D202DC5E290C486F5855CBD6A8470AE62CA96245834CF49257D8D"
+ "96D4041B15007650DEE668C00DDBF749054256C571F60980AC74D0DBCA7FB96C2F48"
+ }, {
+ "NIST P-521", 1,
+ "822A846606DC9E96452CAC373567A8B57D9ACA15B177F75DD7EF10C635F52CE4"
+ "EF6ABEEDB90D3F48F50A0C9015A95C955A25C45DE8413DE3BF899B6B1E62CF7CB8",
+ "0102771B5F3EC8C36838CEC04DCBC28AD1E38C37DAB0EA89B5EE92D21F7A35CE"
+ "ABC8B155EDC70154D6DFA2E77EC1D8C4A3406A6BD0ECF8F1EE2AC33A02464CB70C97"
+ }, {
+ "NIST P-521", 0,
+ "F733D48467912D1FFE46CF442F27FDD218D190E7B8A829D822DA3B6BAF9B987E"
+ "5B4BCCE34499248F59EEAF74F63ED15FF73F243C6FC3FD5E5842F6A3BA34C2022D",
+ "0281AAAD1B7EEBABEB6EC67932CB7E95717AFA3B4CF7A2DB151CD537C419C3A5"
+ "156ED9160758190B47696CDC15E81BBAD12975283907A571604DB23F702AEA4B38FF"
+ }, {
+ "NIST P-521", 0,
+ "03B1B274175AAEB5907152E5114CCAEADA28A7ADD4A2B1831C3D8302E8596489"
+ "E2C98B9B8D0CAE98C03BB11E28CE66D4736449758AF58BAFE40EF5A5FA22C9A43117",
+ "94C5951F81D544E959EDFC5DC1D5F42FE427871D4FB91A43A0B4A6BEA6B35B9E"
+ "BC5FB444C70BE4FD47B4ED16704F8C86EF019FC47C7FF2271F8B0DDEA9E2D3BCDD"
+ }, {
+ "NIST P-521", 1,
+ "F2248C318055DE37CD706D4FCAF7E7D96737A4A7B6B8067A66DCD58B6B8DFC55"
+ "90ECE67F6AA67F9C51B57E7B023075F2F42909BF47361CB6881C10F55FB7215B56",
+ "0162F735CE6A2ADA54CAF96A12D6888C02DE0A74638CF34CE39DABBACA4D651B"
+ "7E6ED1A65B551B36BAE7BE474BB6E6905ED0E33C7BA2021885027C7C6E40C5613004"
+ }, {
+ "NIST P-521", 0,
+ "9F08E97FEADCF0A391CA1EA4D97B5FE62D3B164593E12027EB967BD6E1FA841A"
+ "9831158DF164BCAD0BF3ADA96127745E25F349BDDD52EEA1654892B35960C9C023",
+ "AE2A25F5440F258AFACA6925C4C9F7AEAD3CB67153C4FACB31AC33F58B43A78C"
+ "B14F682FF726CEE2A6B6F6B481AEEB29A9B3150F02D1CFB764672BA8294C477291"
+ }, {
+ "NIST P-521", 0,
+ "01047B52014748C904980716953206A93F0D01B34CA94A997407FA93FE304F86"
+ "17BB6E402B2BB8B434C2671ECE953ABE7BADB75713CD9DF950943A33A9A19ACCDABE",
+ "7433533F098037DEA616337986887D01C5CC8DEC3DC1FDB9CDF7287EF27CC125"
+ "54FCF3A5E212DF9DAD9F8A3A7173B23FC6E15930704F3AEE1B074BDDB0ED6823E4"
+ }, {
+ "NIST P-521", 0,
+ "01C2A9EBF51592FE6589F618EAADA1697D9B2EC7CE5D48C9E80FC597642B23F1"
+ "F0EBE953449762BD3F094F57791D9850AFE98BBDA9872BE399B7BDD617860076BB03",
+ "0B822E27692F63DB8E12C59BB3CCA172B9BBF613CAE5F9D1474186E45E8B26FF"
+ "962084E1C6BE74821EDBB60941A3B75516F603719563433383812BFEA89EC14B89"
+ }, {
+ "NIST P-521", 0,
+ "99390F342C3F0D46E80C5B65C61E8AA8ACA0B6D4E1352404586364A05D8398E9"
+ "2BC71A644E8663F0A9B87D0B3ACAEE32F2AB9B321317AD23059D045EBAB91C5D93",
+ "82FCF93AE4467EB57766F2B150E736636727E7282500CD482DA70D153D195F2B"
+ "DF9B96D689A0DC1BB9137B41557A33F202F1B71840544CBEFF03072E77E4BB6F0B"
+ }, {
+ "NIST P-521", 1,
+ "018E48E80594FF5496D8CC7DF8A19D6AA18805A4EF4490038AED6A1E9AA18056"
+ "D0244A97DCF6D132C6804E3F4F369922119544B4C057D783C848FB798B48730A382C",
+ "01AF510B4F5E1C40BC9C110216D35E7C6D7A2BEE52914FC98258676288449901"
+ "F27A07EE91DF2D5D79259712906C3E18A990CBF35BCAC41A952820CE2BA8D0220080"
+ }, {
+ "NIST P-521", 1,
+ "ADCEF3539B4BC831DC0AFD173137A4426152058AFBAE06A17FCB89F4DB6E48B5"
+ "335CB88F8E4DB475A1E390E5656072F06605BFB84CBF9795B7992ECA04A8E10CA1",
+ "01BCB985AFD6404B9EDA49B6190AAA346BF7D5909CA440C0F7E505C62FAC8635"
+ "31D3EB7B2AC4DD4F4404E4B12E9D6D3C596179587F3724B1EFFF684CFDB4B21826B9"
+ }
+ };
+ gpg_error_t err;
+ int tidx;
+ const char *lastcurve = NULL;
+ gcry_ctx_t ctx = NULL;
+ gcry_mpi_t qx = NULL;
+ gcry_mpi_t qy = NULL;
+ gcry_mpi_point_t Q;
+ int oncurve;
+
+ wherestr = "point_on_curve";
+ for (tidx=0; tidx < DIM (t); tidx++)
+ {
+ if (!t[tidx].curve)
+ {
+ if (!lastcurve || !ctx)
+ die ("invalid test vectors at idx %d\n", tidx);
+ }
+ else if (!ctx || !lastcurve || strcmp (t[tidx].curve, lastcurve))
+ {
+ lastcurve = t[tidx].curve;
+ gcry_ctx_release (ctx);
+ err = gcry_mpi_ec_new (&ctx, NULL, lastcurve);
+ if (err)
+ die ("error creating context for curve %s at idx %d: %s\n",
+ lastcurve, tidx, gpg_strerror (err));
+
+ info ("checking points on curve %s\n", lastcurve);
+ }
+
+ gcry_mpi_release (qx);
+ gcry_mpi_release (qy);
+ qx = hex2mpi (t[tidx].qx);
+ qy = hex2mpi (t[tidx].qy);
+
+ Q = gcry_mpi_point_set (NULL, qx, qy, GCRYMPI_CONST_ONE);
+ if (!Q)
+ die ("gcry_mpi_point_set(Q) failed at idx %d\n", tidx);
+
+ oncurve = gcry_mpi_ec_curve_point (Q, ctx);
+
+ if (t[tidx].oncurve && !oncurve)
+ {
+ fail ("point expected on curve but not identified as such (i=%d):\n",
+ tidx);
+ print_point (" Q", Q);
+ }
+ else if (!t[tidx].oncurve && oncurve)
+ {
+ fail ("point not expected on curve but identified as such (i=%d):\n",
+ tidx);
+ print_point (" Q", Q);
+ }
+ gcry_mpi_point_release (Q);
+ }
+
+ gcry_mpi_release (qx);
+ gcry_mpi_release (qy);
+ gcry_ctx_release (ctx);
+}
+
+
int
main (int argc, char **argv)
{
context_alloc ();
context_param ();
basic_ec_math ();
+ point_on_curve ();
/* The tests are for P-192 and ed25519 which are not supported in
FIPS mode. */
#include <stdlib.h>
#include <string.h>
#include <errno.h>
+#include <unistd.h>
#define PGM "t-secmem"
#include "../src/gcrypt-testapi.h"
+#define DEFAULT_PAGE_SIZE 4096
+#define MINIMUM_POOL_SIZE 16384
+static size_t pool_size;
+static size_t chunk_size;
+
static void
test_secmem (void)
{
memset (a, 0, sizeof a);
/* Allocating 28*512=14k should work in the default 16k pool even
- * with extrem alignment requirements. */
+ * with extra alignment requirements. */
for (i=0; i < DIM(a); i++)
- a[i] = gcry_xmalloc_secure (512);
+ a[i] = gcry_xmalloc_secure (chunk_size);
/* Allocating another 2k should fail for the default 16k pool. */
- b = gcry_malloc_secure (2048);
+ b = gcry_malloc_secure (chunk_size*4);
if (b)
fail ("allocation did not fail as expected\n");
/* Allocating 150*512=75k should require more than one overflow buffer. */
for (i=0; i < DIM(a); i++)
{
- a[i] = gcry_xmalloc_secure (512);
+ a[i] = gcry_xmalloc_secure (chunk_size);
if (verbose && !(i %40))
xgcry_control (GCRYCTL_DUMP_SECMEM_STATS, 0 , 0);
}
main (int argc, char **argv)
{
int last_argc = -1;
+ long int pgsize_val = -1;
+ size_t pgsize;
+
+#if HAVE_MMAP
+# if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
+ pgsize_val = sysconf (_SC_PAGESIZE);
+# elif defined(HAVE_GETPAGESIZE)
+ pgsize_val = getpagesize ();
+# endif
+#endif
+ pgsize = (pgsize_val > 0)? pgsize_val : DEFAULT_PAGE_SIZE;
+
+ pool_size = (MINIMUM_POOL_SIZE + pgsize - 1) & ~(pgsize - 1);
+ chunk_size = pool_size / 32;
if (argc)
{ argc--; argv++; }
if (debug)
xgcry_control (GCRYCTL_SET_DEBUG_FLAGS, 1u , 0);
xgcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0);
- xgcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
+ xgcry_control (GCRYCTL_INIT_SECMEM, pool_size, 0);
gcry_set_outofcore_handler (outofcore_handler, NULL);
xgcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
projects / platform / upstream / libgcrypt.git / commitdiff