3 * PKCS stuff for rsa-sha256.
6 /* nettle, low-level cryptographics library
8 * Copyright (C) 2001, 2003, 2006 Niels Möller
10 * The nettle library is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU Lesser General Public License as published by
12 * the Free Software Foundation; either version 2.1 of the License, or (at your
13 * option) any later version.
15 * The nettle library is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
17 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
18 * License for more details.
20 * You should have received a copy of the GNU Lesser General Public License
21 * along with the nettle library; see the file COPYING.LIB. If not, write to
22 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
39 #include "nettle-internal.h"
41 /* From RFC 3447, Public-Key Cryptography Standards (PKCS) #1: RSA
42 * Cryptography Specifications Version 2.1.
44 * id-sha256 OBJECT IDENTIFIER ::=
45 * {joint-iso-itu-t(2) country(16) us(840) organization(1)
46 * gov(101) csor(3) nistalgorithm(4) hashalgs(2) 1}
52 /* 19 octets prefix, 32 octets hash, total 51 */
53 0x30, 49, /* SEQUENCE */
54 0x30, 13, /* SEQUENCE */
55 0x06, 9, /* OBJECT IDENTIFIER */
56 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
58 0x04, 32 /* OCTET STRING */
59 /* Here comes the raw hash value */
63 pkcs1_rsa_sha256_encode(mpz_t m, unsigned size, struct sha256_ctx *hash)
65 TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_BITS / 8);
68 if (pkcs1_signature_prefix(size, em,
69 sizeof(sha256_prefix),
73 sha256_digest(hash, SHA256_DIGEST_SIZE, em + size - SHA256_DIGEST_SIZE);
74 nettle_mpz_set_str_256_u(m, size, em);
82 pkcs1_rsa_sha256_encode_digest(mpz_t m, unsigned size, const uint8_t *digest)
84 TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_BITS / 8);
87 if (pkcs1_signature_prefix(size, em,
88 sizeof(sha256_prefix),
92 memcpy(em + size - SHA256_DIGEST_SIZE, digest, SHA256_DIGEST_SIZE);
93 nettle_mpz_set_str_256_u(m, size, em);