4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
5 * SPDX-License-Identifier: Apache-2.0
7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
8 * not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
19 * This file is part of mbed TLS (https://tls.mbed.org)
25 * SEC1 http://www.secg.org/index.php?action=secg,docs_secg
28 #if !defined(MBEDTLS_CONFIG_FILE)
29 #include "mbedtls/config.h"
31 #include MBEDTLS_CONFIG_FILE
34 #if defined(MBEDTLS_ECDSA_C)
36 #include "mbedtls/ecdsa.h"
37 #include "mbedtls/asn1write.h"
41 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
42 #include "mbedtls/hmac_drbg.h"
45 #if defined(MBEDTLS_PLATFORM_C)
46 #include "mbedtls/platform.h"
49 #define mbedtls_calloc calloc
50 #define mbedtls_free free
53 #include "mbedtls/platform_util.h"
55 /* Parameter validation macros based on platform_util.h */
56 #define ECDSA_VALIDATE_RET( cond ) \
57 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ECP_BAD_INPUT_DATA )
58 #define ECDSA_VALIDATE( cond ) \
59 MBEDTLS_INTERNAL_VALIDATE( cond )
61 #if defined(MBEDTLS_ECP_RESTARTABLE)
64 * Sub-context for ecdsa_verify()
66 struct mbedtls_ecdsa_restart_ver
68 mbedtls_mpi u1, u2; /* intermediate values */
69 enum { /* what to do next? */
70 ecdsa_ver_init = 0, /* getting started */
71 ecdsa_ver_muladd, /* muladd step */
76 * Init verify restart sub-context
78 static void ecdsa_restart_ver_init( mbedtls_ecdsa_restart_ver_ctx *ctx )
80 mbedtls_mpi_init( &ctx->u1 );
81 mbedtls_mpi_init( &ctx->u2 );
82 ctx->state = ecdsa_ver_init;
86 * Free the components of a verify restart sub-context
88 static void ecdsa_restart_ver_free( mbedtls_ecdsa_restart_ver_ctx *ctx )
93 mbedtls_mpi_free( &ctx->u1 );
94 mbedtls_mpi_free( &ctx->u2 );
96 ecdsa_restart_ver_init( ctx );
100 * Sub-context for ecdsa_sign()
102 struct mbedtls_ecdsa_restart_sig
106 mbedtls_mpi k; /* per-signature random */
107 mbedtls_mpi r; /* r value */
108 enum { /* what to do next? */
109 ecdsa_sig_init = 0, /* getting started */
110 ecdsa_sig_mul, /* doing ecp_mul() */
111 ecdsa_sig_modn, /* mod N computations */
116 * Init verify sign sub-context
118 static void ecdsa_restart_sig_init( mbedtls_ecdsa_restart_sig_ctx *ctx )
122 mbedtls_mpi_init( &ctx->k );
123 mbedtls_mpi_init( &ctx->r );
124 ctx->state = ecdsa_sig_init;
128 * Free the components of a sign restart sub-context
130 static void ecdsa_restart_sig_free( mbedtls_ecdsa_restart_sig_ctx *ctx )
135 mbedtls_mpi_free( &ctx->k );
136 mbedtls_mpi_free( &ctx->r );
139 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
141 * Sub-context for ecdsa_sign_det()
143 struct mbedtls_ecdsa_restart_det
145 mbedtls_hmac_drbg_context rng_ctx; /* DRBG state */
146 enum { /* what to do next? */
147 ecdsa_det_init = 0, /* getting started */
148 ecdsa_det_sign, /* make signature */
153 * Init verify sign_det sub-context
155 static void ecdsa_restart_det_init( mbedtls_ecdsa_restart_det_ctx *ctx )
157 mbedtls_hmac_drbg_init( &ctx->rng_ctx );
158 ctx->state = ecdsa_det_init;
162 * Free the components of a sign_det restart sub-context
164 static void ecdsa_restart_det_free( mbedtls_ecdsa_restart_det_ctx *ctx )
169 mbedtls_hmac_drbg_free( &ctx->rng_ctx );
171 ecdsa_restart_det_init( ctx );
173 #endif /* MBEDTLS_ECDSA_DETERMINISTIC */
175 #define ECDSA_RS_ECP &rs_ctx->ecp
177 /* Utility macro for checking and updating ops budget */
178 #define ECDSA_BUDGET( ops ) \
179 MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, &rs_ctx->ecp, ops ) );
181 /* Call this when entering a function that needs its own sub-context */
182 #define ECDSA_RS_ENTER( SUB ) do { \
183 /* reset ops count for this call if top-level */ \
184 if( rs_ctx != NULL && rs_ctx->ecp.depth++ == 0 ) \
185 rs_ctx->ecp.ops_done = 0; \
187 /* set up our own sub-context if needed */ \
188 if( mbedtls_ecp_restart_is_enabled() && \
189 rs_ctx != NULL && rs_ctx->SUB == NULL ) \
191 rs_ctx->SUB = mbedtls_calloc( 1, sizeof( *rs_ctx->SUB ) ); \
192 if( rs_ctx->SUB == NULL ) \
193 return( MBEDTLS_ERR_ECP_ALLOC_FAILED ); \
195 ecdsa_restart_## SUB ##_init( rs_ctx->SUB ); \
199 /* Call this when leaving a function that needs its own sub-context */
200 #define ECDSA_RS_LEAVE( SUB ) do { \
201 /* clear our sub-context when not in progress (done or error) */ \
202 if( rs_ctx != NULL && rs_ctx->SUB != NULL && \
203 ret != MBEDTLS_ERR_ECP_IN_PROGRESS ) \
205 ecdsa_restart_## SUB ##_free( rs_ctx->SUB ); \
206 mbedtls_free( rs_ctx->SUB ); \
207 rs_ctx->SUB = NULL; \
210 if( rs_ctx != NULL ) \
211 rs_ctx->ecp.depth--; \
214 #else /* MBEDTLS_ECP_RESTARTABLE */
216 #define ECDSA_RS_ECP NULL
218 #define ECDSA_BUDGET( ops ) /* no-op; for compatibility */
220 #define ECDSA_RS_ENTER( SUB ) (void) rs_ctx
221 #define ECDSA_RS_LEAVE( SUB ) (void) rs_ctx
223 #endif /* MBEDTLS_ECP_RESTARTABLE */
226 * Derive a suitable integer for group grp from a buffer of length len
227 * SEC1 4.1.3 step 5 aka SEC1 4.1.4 step 3
229 static int derive_mpi( const mbedtls_ecp_group *grp, mbedtls_mpi *x,
230 const unsigned char *buf, size_t blen )
233 size_t n_size = ( grp->nbits + 7 ) / 8;
234 size_t use_size = blen > n_size ? n_size : blen;
236 MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( x, buf, use_size ) );
237 if( use_size * 8 > grp->nbits )
238 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( x, use_size * 8 - grp->nbits ) );
240 /* While at it, reduce modulo N */
241 if( mbedtls_mpi_cmp_mpi( x, &grp->N ) >= 0 )
242 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( x, x, &grp->N ) );
248 #if !defined(MBEDTLS_ECDSA_SIGN_ALT)
250 * Compute ECDSA signature of a hashed message (SEC1 4.1.3)
251 * Obviously, compared to SEC1 4.1.3, we skip step 4 (hash message)
253 static int ecdsa_sign_restartable( mbedtls_ecp_group *grp,
254 mbedtls_mpi *r, mbedtls_mpi *s,
255 const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
256 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
257 mbedtls_ecdsa_restart_ctx *rs_ctx )
259 int ret, key_tries, sign_tries;
260 int *p_sign_tries = &sign_tries, *p_key_tries = &key_tries;
263 mbedtls_mpi *pk = &k, *pr = r;
265 /* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */
266 if( grp->N.p == NULL )
267 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
269 /* Make sure d is in range 1..n-1 */
270 if( mbedtls_mpi_cmp_int( d, 1 ) < 0 || mbedtls_mpi_cmp_mpi( d, &grp->N ) >= 0 )
271 return( MBEDTLS_ERR_ECP_INVALID_KEY );
273 mbedtls_ecp_point_init( &R );
274 mbedtls_mpi_init( &k ); mbedtls_mpi_init( &e ); mbedtls_mpi_init( &t );
276 ECDSA_RS_ENTER( sig );
278 #if defined(MBEDTLS_ECP_RESTARTABLE)
279 if( rs_ctx != NULL && rs_ctx->sig != NULL )
281 /* redirect to our context */
282 p_sign_tries = &rs_ctx->sig->sign_tries;
283 p_key_tries = &rs_ctx->sig->key_tries;
284 pk = &rs_ctx->sig->k;
285 pr = &rs_ctx->sig->r;
287 /* jump to current step */
288 if( rs_ctx->sig->state == ecdsa_sig_mul )
290 if( rs_ctx->sig->state == ecdsa_sig_modn )
293 #endif /* MBEDTLS_ECP_RESTARTABLE */
298 if( *p_sign_tries++ > 10 )
300 ret = MBEDTLS_ERR_ECP_RANDOM_FAILED;
305 * Steps 1-3: generate a suitable ephemeral keypair
306 * and set r = xR mod n
311 if( *p_key_tries++ > 10 )
313 ret = MBEDTLS_ERR_ECP_RANDOM_FAILED;
317 MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, pk, f_rng, p_rng ) );
319 #if defined(MBEDTLS_ECP_RESTARTABLE)
320 if( rs_ctx != NULL && rs_ctx->sig != NULL )
321 rs_ctx->sig->state = ecdsa_sig_mul;
325 MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, &R, pk, &grp->G,
326 f_rng, p_rng, ECDSA_RS_ECP ) );
327 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( pr, &R.X, &grp->N ) );
329 while( mbedtls_mpi_cmp_int( pr, 0 ) == 0 );
331 #if defined(MBEDTLS_ECP_RESTARTABLE)
332 if( rs_ctx != NULL && rs_ctx->sig != NULL )
333 rs_ctx->sig->state = ecdsa_sig_modn;
338 * Accounting for everything up to the end of the loop
339 * (step 6, but checking now avoids saving e and t)
341 ECDSA_BUDGET( MBEDTLS_ECP_OPS_INV + 4 );
344 * Step 5: derive MPI from hashed message
346 MBEDTLS_MPI_CHK( derive_mpi( grp, &e, buf, blen ) );
349 * Generate a random value to blind inv_mod in next step,
350 * avoiding a potential timing leak.
352 MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, &t, f_rng, p_rng ) );
355 * Step 6: compute s = (e + r * d) / k = t (e + rd) / (kt) mod n
357 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( s, pr, d ) );
358 MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &e, &e, s ) );
359 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &e, &e, &t ) );
360 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( pk, pk, &t ) );
361 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( s, pk, &grp->N ) );
362 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( s, s, &e ) );
363 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( s, s, &grp->N ) );
365 while( mbedtls_mpi_cmp_int( s, 0 ) == 0 );
367 #if defined(MBEDTLS_ECP_RESTARTABLE)
368 if( rs_ctx != NULL && rs_ctx->sig != NULL )
369 mbedtls_mpi_copy( r, pr );
373 mbedtls_ecp_point_free( &R );
374 mbedtls_mpi_free( &k ); mbedtls_mpi_free( &e ); mbedtls_mpi_free( &t );
376 ECDSA_RS_LEAVE( sig );
382 * Compute ECDSA signature of a hashed message
384 int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
385 const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
386 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
388 ECDSA_VALIDATE_RET( grp != NULL );
389 ECDSA_VALIDATE_RET( r != NULL );
390 ECDSA_VALIDATE_RET( s != NULL );
391 ECDSA_VALIDATE_RET( d != NULL );
392 ECDSA_VALIDATE_RET( f_rng != NULL );
393 ECDSA_VALIDATE_RET( buf != NULL || blen == 0 );
395 return( ecdsa_sign_restartable( grp, r, s, d, buf, blen,
396 f_rng, p_rng, NULL ) );
398 #endif /* !MBEDTLS_ECDSA_SIGN_ALT */
400 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
402 * Deterministic signature wrapper
404 static int ecdsa_sign_det_restartable( mbedtls_ecp_group *grp,
405 mbedtls_mpi *r, mbedtls_mpi *s,
406 const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
407 mbedtls_md_type_t md_alg,
408 mbedtls_ecdsa_restart_ctx *rs_ctx )
411 mbedtls_hmac_drbg_context rng_ctx;
412 mbedtls_hmac_drbg_context *p_rng = &rng_ctx;
413 unsigned char data[2 * MBEDTLS_ECP_MAX_BYTES];
414 size_t grp_len = ( grp->nbits + 7 ) / 8;
415 const mbedtls_md_info_t *md_info;
418 if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL )
419 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
421 mbedtls_mpi_init( &h );
422 mbedtls_hmac_drbg_init( &rng_ctx );
424 ECDSA_RS_ENTER( det );
426 #if defined(MBEDTLS_ECP_RESTARTABLE)
427 if( rs_ctx != NULL && rs_ctx->det != NULL )
429 /* redirect to our context */
430 p_rng = &rs_ctx->det->rng_ctx;
432 /* jump to current step */
433 if( rs_ctx->det->state == ecdsa_det_sign )
436 #endif /* MBEDTLS_ECP_RESTARTABLE */
438 /* Use private key and message hash (reduced) to initialize HMAC_DRBG */
439 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( d, data, grp_len ) );
440 MBEDTLS_MPI_CHK( derive_mpi( grp, &h, buf, blen ) );
441 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &h, data + grp_len, grp_len ) );
442 mbedtls_hmac_drbg_seed_buf( p_rng, md_info, data, 2 * grp_len );
444 #if defined(MBEDTLS_ECP_RESTARTABLE)
445 if( rs_ctx != NULL && rs_ctx->det != NULL )
446 rs_ctx->det->state = ecdsa_det_sign;
450 #if defined(MBEDTLS_ECDSA_SIGN_ALT)
451 ret = mbedtls_ecdsa_sign( grp, r, s, d, buf, blen,
452 mbedtls_hmac_drbg_random, p_rng );
454 ret = ecdsa_sign_restartable( grp, r, s, d, buf, blen,
455 mbedtls_hmac_drbg_random, p_rng, rs_ctx );
456 #endif /* MBEDTLS_ECDSA_SIGN_ALT */
459 mbedtls_hmac_drbg_free( &rng_ctx );
460 mbedtls_mpi_free( &h );
462 ECDSA_RS_LEAVE( det );
468 * Deterministic signature wrapper
470 int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
471 const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
472 mbedtls_md_type_t md_alg )
474 ECDSA_VALIDATE_RET( grp != NULL );
475 ECDSA_VALIDATE_RET( r != NULL );
476 ECDSA_VALIDATE_RET( s != NULL );
477 ECDSA_VALIDATE_RET( d != NULL );
478 ECDSA_VALIDATE_RET( buf != NULL || blen == 0 );
480 return( ecdsa_sign_det_restartable( grp, r, s, d, buf, blen, md_alg, NULL ) );
482 #endif /* MBEDTLS_ECDSA_DETERMINISTIC */
484 #if !defined(MBEDTLS_ECDSA_VERIFY_ALT)
486 * Verify ECDSA signature of hashed message (SEC1 4.1.4)
487 * Obviously, compared to SEC1 4.1.3, we skip step 2 (hash message)
489 static int ecdsa_verify_restartable( mbedtls_ecp_group *grp,
490 const unsigned char *buf, size_t blen,
491 const mbedtls_ecp_point *Q,
492 const mbedtls_mpi *r, const mbedtls_mpi *s,
493 mbedtls_ecdsa_restart_ctx *rs_ctx )
496 mbedtls_mpi e, s_inv, u1, u2;
498 mbedtls_mpi *pu1 = &u1, *pu2 = &u2;
500 mbedtls_ecp_point_init( &R );
501 mbedtls_mpi_init( &e ); mbedtls_mpi_init( &s_inv );
502 mbedtls_mpi_init( &u1 ); mbedtls_mpi_init( &u2 );
504 /* Fail cleanly on curves such as Curve25519 that can't be used for ECDSA */
505 if( grp->N.p == NULL )
506 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
508 ECDSA_RS_ENTER( ver );
510 #if defined(MBEDTLS_ECP_RESTARTABLE)
511 if( rs_ctx != NULL && rs_ctx->ver != NULL )
513 /* redirect to our context */
514 pu1 = &rs_ctx->ver->u1;
515 pu2 = &rs_ctx->ver->u2;
517 /* jump to current step */
518 if( rs_ctx->ver->state == ecdsa_ver_muladd )
521 #endif /* MBEDTLS_ECP_RESTARTABLE */
524 * Step 1: make sure r and s are in range 1..n-1
526 if( mbedtls_mpi_cmp_int( r, 1 ) < 0 || mbedtls_mpi_cmp_mpi( r, &grp->N ) >= 0 ||
527 mbedtls_mpi_cmp_int( s, 1 ) < 0 || mbedtls_mpi_cmp_mpi( s, &grp->N ) >= 0 )
529 ret = MBEDTLS_ERR_ECP_VERIFY_FAILED;
534 * Step 3: derive MPI from hashed message
536 MBEDTLS_MPI_CHK( derive_mpi( grp, &e, buf, blen ) );
539 * Step 4: u1 = e / s mod n, u2 = r / s mod n
541 ECDSA_BUDGET( MBEDTLS_ECP_OPS_CHK + MBEDTLS_ECP_OPS_INV + 2 );
543 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &s_inv, s, &grp->N ) );
545 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( pu1, &e, &s_inv ) );
546 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( pu1, pu1, &grp->N ) );
548 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( pu2, r, &s_inv ) );
549 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( pu2, pu2, &grp->N ) );
551 #if defined(MBEDTLS_ECP_RESTARTABLE)
552 if( rs_ctx != NULL && rs_ctx->ver != NULL )
553 rs_ctx->ver->state = ecdsa_ver_muladd;
558 * Step 5: R = u1 G + u2 Q
560 MBEDTLS_MPI_CHK( mbedtls_ecp_muladd_restartable( grp,
561 &R, pu1, &grp->G, pu2, Q, ECDSA_RS_ECP ) );
563 if( mbedtls_ecp_is_zero( &R ) )
565 ret = MBEDTLS_ERR_ECP_VERIFY_FAILED;
570 * Step 6: convert xR to an integer (no-op)
571 * Step 7: reduce xR mod n (gives v)
573 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &R.X, &R.X, &grp->N ) );
576 * Step 8: check if v (that is, R.X) is equal to r
578 if( mbedtls_mpi_cmp_mpi( &R.X, r ) != 0 )
580 ret = MBEDTLS_ERR_ECP_VERIFY_FAILED;
585 mbedtls_ecp_point_free( &R );
586 mbedtls_mpi_free( &e ); mbedtls_mpi_free( &s_inv );
587 mbedtls_mpi_free( &u1 ); mbedtls_mpi_free( &u2 );
589 ECDSA_RS_LEAVE( ver );
595 * Verify ECDSA signature of hashed message
597 int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
598 const unsigned char *buf, size_t blen,
599 const mbedtls_ecp_point *Q,
600 const mbedtls_mpi *r,
601 const mbedtls_mpi *s)
603 ECDSA_VALIDATE_RET( grp != NULL );
604 ECDSA_VALIDATE_RET( Q != NULL );
605 ECDSA_VALIDATE_RET( r != NULL );
606 ECDSA_VALIDATE_RET( s != NULL );
607 ECDSA_VALIDATE_RET( buf != NULL || blen == 0 );
609 return( ecdsa_verify_restartable( grp, buf, blen, Q, r, s, NULL ) );
611 #endif /* !MBEDTLS_ECDSA_VERIFY_ALT */
614 * Convert a signature (given by context) to ASN.1
616 static int ecdsa_signature_to_asn1( const mbedtls_mpi *r, const mbedtls_mpi *s,
617 unsigned char *sig, size_t *slen )
620 unsigned char buf[MBEDTLS_ECDSA_MAX_LEN];
621 unsigned char *p = buf + sizeof( buf );
624 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &p, buf, s ) );
625 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &p, buf, r ) );
627 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &p, buf, len ) );
628 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &p, buf,
629 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
631 memcpy( sig, p, len );
638 * Compute and write signature
640 int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx,
641 mbedtls_md_type_t md_alg,
642 const unsigned char *hash, size_t hlen,
643 unsigned char *sig, size_t *slen,
644 int (*f_rng)(void *, unsigned char *, size_t),
646 mbedtls_ecdsa_restart_ctx *rs_ctx )
650 ECDSA_VALIDATE_RET( ctx != NULL );
651 ECDSA_VALIDATE_RET( hash != NULL );
652 ECDSA_VALIDATE_RET( sig != NULL );
653 ECDSA_VALIDATE_RET( slen != NULL );
655 mbedtls_mpi_init( &r );
656 mbedtls_mpi_init( &s );
658 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
662 MBEDTLS_MPI_CHK( ecdsa_sign_det_restartable( &ctx->grp, &r, &s, &ctx->d,
663 hash, hlen, md_alg, rs_ctx ) );
667 #if defined(MBEDTLS_ECDSA_SIGN_ALT)
668 MBEDTLS_MPI_CHK( mbedtls_ecdsa_sign( &ctx->grp, &r, &s, &ctx->d,
669 hash, hlen, f_rng, p_rng ) );
671 MBEDTLS_MPI_CHK( ecdsa_sign_restartable( &ctx->grp, &r, &s, &ctx->d,
672 hash, hlen, f_rng, p_rng, rs_ctx ) );
673 #endif /* MBEDTLS_ECDSA_SIGN_ALT */
674 #endif /* MBEDTLS_ECDSA_DETERMINISTIC */
676 MBEDTLS_MPI_CHK( ecdsa_signature_to_asn1( &r, &s, sig, slen ) );
679 mbedtls_mpi_free( &r );
680 mbedtls_mpi_free( &s );
686 * Compute and write signature
688 int mbedtls_ecdsa_write_signature( mbedtls_ecdsa_context *ctx,
689 mbedtls_md_type_t md_alg,
690 const unsigned char *hash, size_t hlen,
691 unsigned char *sig, size_t *slen,
692 int (*f_rng)(void *, unsigned char *, size_t),
695 ECDSA_VALIDATE_RET( ctx != NULL );
696 ECDSA_VALIDATE_RET( hash != NULL );
697 ECDSA_VALIDATE_RET( sig != NULL );
698 ECDSA_VALIDATE_RET( slen != NULL );
699 return( mbedtls_ecdsa_write_signature_restartable(
700 ctx, md_alg, hash, hlen, sig, slen, f_rng, p_rng, NULL ) );
703 #if !defined(MBEDTLS_DEPRECATED_REMOVED) && \
704 defined(MBEDTLS_ECDSA_DETERMINISTIC)
705 int mbedtls_ecdsa_write_signature_det( mbedtls_ecdsa_context *ctx,
706 const unsigned char *hash, size_t hlen,
707 unsigned char *sig, size_t *slen,
708 mbedtls_md_type_t md_alg )
710 ECDSA_VALIDATE_RET( ctx != NULL );
711 ECDSA_VALIDATE_RET( hash != NULL );
712 ECDSA_VALIDATE_RET( sig != NULL );
713 ECDSA_VALIDATE_RET( slen != NULL );
714 return( mbedtls_ecdsa_write_signature( ctx, md_alg, hash, hlen, sig, slen,
720 * Read and check signature
722 int mbedtls_ecdsa_read_signature( mbedtls_ecdsa_context *ctx,
723 const unsigned char *hash, size_t hlen,
724 const unsigned char *sig, size_t slen )
726 ECDSA_VALIDATE_RET( ctx != NULL );
727 ECDSA_VALIDATE_RET( hash != NULL );
728 ECDSA_VALIDATE_RET( sig != NULL );
729 return( mbedtls_ecdsa_read_signature_restartable(
730 ctx, hash, hlen, sig, slen, NULL ) );
734 * Restartable read and check signature
736 int mbedtls_ecdsa_read_signature_restartable( mbedtls_ecdsa_context *ctx,
737 const unsigned char *hash, size_t hlen,
738 const unsigned char *sig, size_t slen,
739 mbedtls_ecdsa_restart_ctx *rs_ctx )
742 unsigned char *p = (unsigned char *) sig;
743 const unsigned char *end = sig + slen;
746 ECDSA_VALIDATE_RET( ctx != NULL );
747 ECDSA_VALIDATE_RET( hash != NULL );
748 ECDSA_VALIDATE_RET( sig != NULL );
750 mbedtls_mpi_init( &r );
751 mbedtls_mpi_init( &s );
753 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
754 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
756 ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
762 ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA +
763 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
767 if( ( ret = mbedtls_asn1_get_mpi( &p, end, &r ) ) != 0 ||
768 ( ret = mbedtls_asn1_get_mpi( &p, end, &s ) ) != 0 )
770 ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
773 #if defined(MBEDTLS_ECDSA_VERIFY_ALT)
774 if( ( ret = mbedtls_ecdsa_verify( &ctx->grp, hash, hlen,
775 &ctx->Q, &r, &s ) ) != 0 )
778 if( ( ret = ecdsa_verify_restartable( &ctx->grp, hash, hlen,
779 &ctx->Q, &r, &s, rs_ctx ) ) != 0 )
781 #endif /* MBEDTLS_ECDSA_VERIFY_ALT */
783 /* At this point we know that the buffer starts with a valid signature.
784 * Return 0 if the buffer just contains the signature, and a specific
785 * error code if the valid signature is followed by more data. */
787 ret = MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH;
790 mbedtls_mpi_free( &r );
791 mbedtls_mpi_free( &s );
796 #if !defined(MBEDTLS_ECDSA_GENKEY_ALT)
800 int mbedtls_ecdsa_genkey( mbedtls_ecdsa_context *ctx, mbedtls_ecp_group_id gid,
801 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
804 ECDSA_VALIDATE_RET( ctx != NULL );
805 ECDSA_VALIDATE_RET( f_rng != NULL );
807 ret = mbedtls_ecp_group_load( &ctx->grp, gid );
811 return( mbedtls_ecp_gen_keypair( &ctx->grp, &ctx->d,
812 &ctx->Q, f_rng, p_rng ) );
814 #endif /* !MBEDTLS_ECDSA_GENKEY_ALT */
817 * Set context from an mbedtls_ecp_keypair
819 int mbedtls_ecdsa_from_keypair( mbedtls_ecdsa_context *ctx, const mbedtls_ecp_keypair *key )
822 ECDSA_VALIDATE_RET( ctx != NULL );
823 ECDSA_VALIDATE_RET( key != NULL );
825 if( ( ret = mbedtls_ecp_group_copy( &ctx->grp, &key->grp ) ) != 0 ||
826 ( ret = mbedtls_mpi_copy( &ctx->d, &key->d ) ) != 0 ||
827 ( ret = mbedtls_ecp_copy( &ctx->Q, &key->Q ) ) != 0 )
829 mbedtls_ecdsa_free( ctx );
838 void mbedtls_ecdsa_init( mbedtls_ecdsa_context *ctx )
840 ECDSA_VALIDATE( ctx != NULL );
842 mbedtls_ecp_keypair_init( ctx );
848 void mbedtls_ecdsa_free( mbedtls_ecdsa_context *ctx )
853 mbedtls_ecp_keypair_free( ctx );
856 #if defined(MBEDTLS_ECP_RESTARTABLE)
858 * Initialize a restart context
860 void mbedtls_ecdsa_restart_init( mbedtls_ecdsa_restart_ctx *ctx )
862 ECDSA_VALIDATE( ctx != NULL );
864 mbedtls_ecp_restart_init( &ctx->ecp );
868 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
874 * Free the components of a restart context
876 void mbedtls_ecdsa_restart_free( mbedtls_ecdsa_restart_ctx *ctx )
881 mbedtls_ecp_restart_free( &ctx->ecp );
883 ecdsa_restart_ver_free( ctx->ver );
884 mbedtls_free( ctx->ver );
887 ecdsa_restart_sig_free( ctx->sig );
888 mbedtls_free( ctx->sig );
891 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
892 ecdsa_restart_det_free( ctx->det );
893 mbedtls_free( ctx->det );
897 #endif /* MBEDTLS_ECP_RESTARTABLE */
899 #endif /* MBEDTLS_ECDSA_C */