2 * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright 2017 Ribose Inc. All Rights Reserved.
4 * Ported from Ribose contributions from Botan.
6 * Licensed under the OpenSSL license (the "License"). You may not use
7 * this file except in compliance with the License. You can obtain a copy
8 * in the file LICENSE in the source distribution or at
9 * https://www.openssl.org/source/license.html
12 #include "internal/sm2.h"
13 #include "internal/sm2err.h"
14 #include <openssl/err.h>
15 #include <openssl/evp.h>
16 #include <openssl/err.h>
17 #include <openssl/bn.h>
20 static BIGNUM *sm2_compute_msg_hash(const EVP_MD *digest,
23 const uint8_t *msg, size_t msg_len)
25 EVP_MD_CTX *hash = EVP_MD_CTX_new();
26 const int md_size = EVP_MD_size(digest);
27 uint8_t *za = OPENSSL_zalloc(md_size);
30 if (hash == NULL || za == NULL) {
31 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, ERR_R_MALLOC_FAILURE);
36 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, SM2_R_INVALID_DIGEST);
40 if (!sm2_compute_userid_digest(za, digest, user_id, key)) {
41 /* SM2err already called */
45 if (!EVP_DigestInit(hash, digest)
46 || !EVP_DigestUpdate(hash, za, md_size)
47 || !EVP_DigestUpdate(hash, msg, msg_len)
48 /* reuse za buffer to hold H(ZA || M) */
49 || !EVP_DigestFinal(hash, za, NULL)) {
50 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, ERR_R_EVP_LIB);
54 e = BN_bin2bn(za, md_size, NULL);
56 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, ERR_R_INTERNAL_ERROR);
60 EVP_MD_CTX_free(hash);
64 static ECDSA_SIG *sm2_sig_gen(const EC_KEY *key, const BIGNUM *e)
66 const BIGNUM *dA = EC_KEY_get0_private_key(key);
67 const EC_GROUP *group = EC_KEY_get0_group(key);
68 const BIGNUM *order = EC_GROUP_get0_order(group);
69 ECDSA_SIG *sig = NULL;
79 kG = EC_POINT_new(group);
81 if (kG == NULL || ctx == NULL) {
82 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
91 tmp = BN_CTX_get(ctx);
93 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
98 * These values are returned and so should not be allocated out of the
104 if (r == NULL || s == NULL) {
105 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
110 if (!BN_priv_rand_range(k, order)) {
111 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_INTERNAL_ERROR);
115 if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
116 || !EC_POINT_get_affine_coordinates_GFp(group, kG, x1, NULL,
118 || !BN_mod_add(r, e, x1, order, ctx)) {
119 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_INTERNAL_ERROR);
123 /* try again if r == 0 or r+k == n */
127 if (!BN_add(rk, r, k)) {
128 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_INTERNAL_ERROR);
132 if (BN_cmp(rk, order) == 0)
135 if (!BN_add(s, dA, BN_value_one())
136 || !BN_mod_inverse(s, s, order, ctx)
137 || !BN_mod_mul(tmp, dA, r, order, ctx)
138 || !BN_sub(tmp, k, tmp)
139 || !BN_mod_mul(s, s, tmp, order, ctx)) {
140 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_BN_LIB);
144 sig = ECDSA_SIG_new();
146 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
150 /* takes ownership of r and s */
151 ECDSA_SIG_set0(sig, r, s);
166 static int sm2_sig_verify(const EC_KEY *key, const ECDSA_SIG *sig,
170 const EC_GROUP *group = EC_KEY_get0_group(key);
171 const BIGNUM *order = EC_GROUP_get0_order(group);
176 const BIGNUM *r = NULL;
177 const BIGNUM *s = NULL;
180 pt = EC_POINT_new(group);
181 if (ctx == NULL || pt == NULL) {
182 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_MALLOC_FAILURE);
188 x1 = BN_CTX_get(ctx);
190 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_MALLOC_FAILURE);
195 * B1: verify whether r' in [1,n-1], verification failed if not
196 * B2: vefify whether s' in [1,n-1], verification failed if not
197 * B3: set M'~=ZA || M'
198 * B4: calculate e'=Hv(M'~)
199 * B5: calculate t = (r' + s') modn, verification failed if t=0
200 * B6: calculate the point (x1', y1')=[s']G + [t]PA
201 * B7: calculate R=(e'+x1') modn, verfication pass if yes, otherwise failed
204 ECDSA_SIG_get0(sig, &r, &s);
206 if (BN_cmp(r, BN_value_one()) < 0
207 || BN_cmp(s, BN_value_one()) < 0
208 || BN_cmp(order, r) <= 0
209 || BN_cmp(order, s) <= 0) {
210 SM2err(SM2_F_SM2_SIG_VERIFY, SM2_R_BAD_SIGNATURE);
214 if (!BN_mod_add(t, r, s, order, ctx)) {
215 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_BN_LIB);
220 SM2err(SM2_F_SM2_SIG_VERIFY, SM2_R_BAD_SIGNATURE);
224 if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
225 || !EC_POINT_get_affine_coordinates_GFp(group, pt, x1, NULL, ctx)) {
226 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_EC_LIB);
230 if (!BN_mod_add(t, e, x1, order, ctx)) {
231 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_BN_LIB);
235 if (BN_cmp(r, t) == 0)
244 ECDSA_SIG *sm2_do_sign(const EC_KEY *key,
245 const EVP_MD *digest,
246 const char *user_id, const uint8_t *msg, size_t msg_len)
249 ECDSA_SIG *sig = NULL;
251 e = sm2_compute_msg_hash(digest, key, user_id, msg, msg_len);
253 /* SM2err already called */
257 sig = sm2_sig_gen(key, e);
264 int sm2_do_verify(const EC_KEY *key,
265 const EVP_MD *digest,
266 const ECDSA_SIG *sig,
267 const char *user_id, const uint8_t *msg, size_t msg_len)
272 e = sm2_compute_msg_hash(digest, key, user_id, msg, msg_len);
274 /* SM2err already called */
278 ret = sm2_sig_verify(key, sig, e);
285 int sm2_sign(const unsigned char *dgst, int dgstlen,
286 unsigned char *sig, unsigned int *siglen, EC_KEY *eckey)
293 e = BN_bin2bn(dgst, dgstlen, NULL);
295 SM2err(SM2_F_SM2_SIGN, ERR_R_BN_LIB);
299 s = sm2_sig_gen(eckey, e);
301 sigleni = i2d_ECDSA_SIG(s, &sig);
303 SM2err(SM2_F_SM2_SIGN, ERR_R_INTERNAL_ERROR);
306 *siglen = (unsigned int)sigleni;
316 int sm2_verify(const unsigned char *dgst, int dgstlen,
317 const unsigned char *sig, int sig_len, EC_KEY *eckey)
321 const unsigned char *p = sig;
322 unsigned char *der = NULL;
328 SM2err(SM2_F_SM2_VERIFY, ERR_R_MALLOC_FAILURE);
331 if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
332 SM2err(SM2_F_SM2_VERIFY, SM2_R_INVALID_ENCODING);
335 /* Ensure signature uses DER and doesn't have trailing garbage */
336 derlen = i2d_ECDSA_SIG(s, &der);
337 if (derlen != sig_len || memcmp(sig, der, derlen) != 0) {
338 SM2err(SM2_F_SM2_VERIFY, SM2_R_INVALID_ENCODING);
342 e = BN_bin2bn(dgst, dgstlen, NULL);
344 SM2err(SM2_F_SM2_VERIFY, ERR_R_BN_LIB);
348 ret = sm2_sig_verify(eckey, s, e);