1 /* crypto/ecdsa/ecs_ossl.c */
3 * Written by Nils Larsch for the OpenSSL project
5 /* ====================================================================
6 * Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@OpenSSL.org.
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
59 #define OPENSSL_FIPSAPI
62 #include <openssl/err.h>
63 #include <openssl/obj_mac.h>
64 #include <openssl/bn.h>
66 static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen,
67 const BIGNUM *, const BIGNUM *, EC_KEY *eckey);
68 static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
70 static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
71 const ECDSA_SIG *sig, EC_KEY *eckey);
73 static ECDSA_METHOD openssl_ecdsa_meth = {
74 "OpenSSL ECDSA method",
82 ECDSA_FLAG_FIPS_METHOD, /* flags */
86 const ECDSA_METHOD *ECDSA_OpenSSL(void)
88 return &openssl_ecdsa_meth;
91 static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
95 BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
96 EC_POINT *tmp_point=NULL;
97 const EC_GROUP *group;
100 if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL)
102 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER);
108 if ((ctx = BN_CTX_new()) == NULL)
110 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_MALLOC_FAILURE);
117 k = BN_new(); /* this value is later returned in *kinvp */
118 r = BN_new(); /* this value is later returned in *rp */
121 if (!k || !r || !order || !X)
123 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
126 if ((tmp_point = EC_POINT_new(group)) == NULL)
128 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
131 if (!EC_GROUP_get_order(group, order, ctx))
133 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
138 if (!fips_check_ec_prng(eckey))
146 if (!BN_rand_range(k, order))
148 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
149 ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
152 while (BN_is_zero(k));
154 #ifdef ECDSA_POINT_MUL_NO_CONSTTIME
155 /* We do not want timing information to leak the length of k,
156 * so we compute G*k using an equivalent scalar of fixed
159 if (!BN_add(k, k, order)) goto err;
160 if (BN_num_bits(k) <= BN_num_bits(order))
161 if (!BN_add(k, k, order)) goto err;
162 #endif /* def(ECDSA_POINT_MUL_NO_CONSTTIME) */
164 /* compute r the x-coordinate of generator * k */
165 if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx))
167 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
170 if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == NID_X9_62_prime_field)
172 if (!EC_POINT_get_affine_coordinates_GFp(group,
173 tmp_point, X, NULL, ctx))
175 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_EC_LIB);
179 #ifndef OPENSSL_NO_EC2M
180 else /* NID_X9_62_characteristic_two_field */
182 if (!EC_POINT_get_affine_coordinates_GF2m(group,
183 tmp_point, X, NULL, ctx))
185 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_EC_LIB);
190 if (!BN_nnmod(r, X, order, ctx))
192 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
196 while (BN_is_zero(r));
198 /* compute the inverse of k */
199 if (!BN_mod_inverse(k, k, order, ctx))
201 ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
204 /* clear old values if necessary */
208 BN_clear_free(*kinvp);
209 /* save the pre-computed values */
216 if (k != NULL) BN_clear_free(k);
217 if (r != NULL) BN_clear_free(r);
223 if (tmp_point != NULL)
224 EC_POINT_free(tmp_point);
231 static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
232 const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *eckey)
235 BIGNUM *kinv=NULL, *s, *m=NULL,*tmp=NULL,*order=NULL;
238 const EC_GROUP *group;
241 const BIGNUM *priv_key;
243 ecdsa = ecdsa_check(eckey);
244 group = EC_KEY_get0_group(eckey);
245 priv_key = EC_KEY_get0_private_key(eckey);
247 if (group == NULL || priv_key == NULL || ecdsa == NULL)
249 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_PASSED_NULL_PARAMETER);
254 if (!fips_check_ec_prng(eckey))
258 ret = ECDSA_SIG_new();
261 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
266 if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
267 (tmp = BN_new()) == NULL || (m = BN_new()) == NULL)
269 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
273 if (!EC_GROUP_get_order(group, order, ctx))
275 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_EC_LIB);
278 i = BN_num_bits(order);
279 /* Need to truncate digest if it is too long: first truncate whole
282 if (8 * dgst_len > i)
283 dgst_len = (i + 7)/8;
284 if (!BN_bin2bn(dgst, dgst_len, m))
286 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
289 /* If still too long truncate remaining bits with a shift */
290 if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7)))
292 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
297 if (in_kinv == NULL || in_r == NULL)
299 if (!ecdsa->meth->ecdsa_sign_setup(eckey, ctx,
302 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,ERR_R_ECDSA_LIB);
310 if (BN_copy(ret->r, in_r) == NULL)
312 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
317 if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx))
319 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
322 if (!BN_mod_add_quick(s, tmp, m, order))
324 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
327 if (!BN_mod_mul(s, s, ckinv, order, ctx))
329 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
334 /* if kinv and r have been supplied by the caller
335 * don't to generate new kinv and r values */
336 if (in_kinv != NULL && in_r != NULL)
338 ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ECDSA_R_NEED_NEW_SETUP_VALUES);
343 /* s != 0 => we have a valid signature */
368 static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
369 const ECDSA_SIG *sig, EC_KEY *eckey)
373 BIGNUM *order, *u1, *u2, *m, *X;
374 EC_POINT *point = NULL;
375 const EC_GROUP *group;
376 const EC_POINT *pub_key;
378 /* check input values */
379 if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
380 (pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL)
382 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_MISSING_PARAMETERS);
389 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
393 order = BN_CTX_get(ctx);
394 u1 = BN_CTX_get(ctx);
395 u2 = BN_CTX_get(ctx);
400 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
404 if (!EC_GROUP_get_order(group, order, ctx))
406 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
410 if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
411 BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||
412 BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0)
414 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_BAD_SIGNATURE);
415 ret = 0; /* signature is invalid */
418 /* calculate tmp1 = inv(S) mod order */
419 if (!BN_mod_inverse(u2, sig->s, order, ctx))
421 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
425 i = BN_num_bits(order);
426 /* Need to truncate digest if it is too long: first truncate whole
429 if (8 * dgst_len > i)
430 dgst_len = (i + 7)/8;
431 if (!BN_bin2bn(dgst, dgst_len, m))
433 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
436 /* If still too long truncate remaining bits with a shift */
437 if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7)))
439 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
442 /* u1 = m * tmp mod order */
443 if (!BN_mod_mul(u1, m, u2, order, ctx))
445 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
448 /* u2 = r * w mod q */
449 if (!BN_mod_mul(u2, sig->r, u2, order, ctx))
451 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
455 if ((point = EC_POINT_new(group)) == NULL)
457 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
460 if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx))
462 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
465 if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == NID_X9_62_prime_field)
467 if (!EC_POINT_get_affine_coordinates_GFp(group,
468 point, X, NULL, ctx))
470 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
474 #ifndef OPENSSL_NO_EC2M
475 else /* NID_X9_62_characteristic_two_field */
477 if (!EC_POINT_get_affine_coordinates_GF2m(group,
478 point, X, NULL, ctx))
480 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
485 if (!BN_nnmod(u1, X, order, ctx))
487 ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
490 /* if the signature is correct u1 is equal to sig->r */
491 ret = (BN_ucmp(u1, sig->r) == 0);
496 EC_POINT_free(point);
500 #ifdef OPENSSL_FIPSCANISTER
501 /* FIPS stanadlone version of ecdsa_check: just return FIPS method */
502 ECDSA_DATA *fips_ecdsa_check(EC_KEY *key)
504 static ECDSA_DATA rv = {
510 /* Standalone digest sign and verify */
511 int FIPS_ecdsa_verify_digest(EC_KEY *key,
512 const unsigned char *dig, int dlen, ECDSA_SIG *s)
514 ECDSA_DATA *ecdsa = ecdsa_check(key);
517 return ecdsa->meth->ecdsa_do_verify(dig, dlen, s, key);
519 ECDSA_SIG * FIPS_ecdsa_sign_digest(EC_KEY *key,
520 const unsigned char *dig, int dlen)
522 ECDSA_DATA *ecdsa = ecdsa_check(key);
525 return ecdsa->meth->ecdsa_do_sign(dig, dlen, NULL, NULL, key);