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 "internal/ec_int.h" /* ec_group_do_inverse_ord() */
15 #include <openssl/err.h>
16 #include <openssl/evp.h>
17 #include <openssl/err.h>
18 #include <openssl/bn.h>
21 int sm2_compute_z_digest(uint8_t *out,
28 const EC_GROUP *group = EC_KEY_get0_group(key);
30 EVP_MD_CTX *hash = NULL;
43 hash = EVP_MD_CTX_new();
45 if (hash == NULL || ctx == NULL) {
46 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_MALLOC_FAILURE);
59 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_MALLOC_FAILURE);
63 if (!EVP_DigestInit(hash, digest)) {
64 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_EVP_LIB);
68 /* Z = h(ENTL || ID || a || b || xG || yG || xA || yA) */
70 if (id_len >= (UINT16_MAX / 8)) {
72 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, SM2_R_ID_TOO_LARGE);
76 entl = (uint16_t)(8 * id_len);
79 if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
80 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_EVP_LIB);
84 if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
85 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_EVP_LIB);
89 if (id_len > 0 && !EVP_DigestUpdate(hash, id, id_len)) {
90 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_EVP_LIB);
94 if (!EC_GROUP_get_curve(group, p, a, b, ctx)) {
95 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_EC_LIB);
99 p_bytes = BN_num_bytes(p);
100 buf = OPENSSL_zalloc(p_bytes);
102 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_MALLOC_FAILURE);
106 if (BN_bn2binpad(a, buf, p_bytes) < 0
107 || !EVP_DigestUpdate(hash, buf, p_bytes)
108 || BN_bn2binpad(b, buf, p_bytes) < 0
109 || !EVP_DigestUpdate(hash, buf, p_bytes)
110 || !EC_POINT_get_affine_coordinates(group,
111 EC_GROUP_get0_generator(group),
113 || BN_bn2binpad(xG, buf, p_bytes) < 0
114 || !EVP_DigestUpdate(hash, buf, p_bytes)
115 || BN_bn2binpad(yG, buf, p_bytes) < 0
116 || !EVP_DigestUpdate(hash, buf, p_bytes)
117 || !EC_POINT_get_affine_coordinates(group,
118 EC_KEY_get0_public_key(key),
120 || BN_bn2binpad(xA, buf, p_bytes) < 0
121 || !EVP_DigestUpdate(hash, buf, p_bytes)
122 || BN_bn2binpad(yA, buf, p_bytes) < 0
123 || !EVP_DigestUpdate(hash, buf, p_bytes)
124 || !EVP_DigestFinal(hash, out, NULL)) {
125 SM2err(SM2_F_SM2_COMPUTE_Z_DIGEST, ERR_R_INTERNAL_ERROR);
134 EVP_MD_CTX_free(hash);
138 static BIGNUM *sm2_compute_msg_hash(const EVP_MD *digest,
142 const uint8_t *msg, size_t msg_len)
144 EVP_MD_CTX *hash = EVP_MD_CTX_new();
145 const int md_size = EVP_MD_size(digest);
150 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, SM2_R_INVALID_DIGEST);
154 z = OPENSSL_zalloc(md_size);
155 if (hash == NULL || z == NULL) {
156 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, ERR_R_MALLOC_FAILURE);
160 if (!sm2_compute_z_digest(z, digest, id, id_len, key)) {
161 /* SM2err already called */
165 if (!EVP_DigestInit(hash, digest)
166 || !EVP_DigestUpdate(hash, z, md_size)
167 || !EVP_DigestUpdate(hash, msg, msg_len)
168 /* reuse z buffer to hold H(Z || M) */
169 || !EVP_DigestFinal(hash, z, NULL)) {
170 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, ERR_R_EVP_LIB);
174 e = BN_bin2bn(z, md_size, NULL);
176 SM2err(SM2_F_SM2_COMPUTE_MSG_HASH, ERR_R_INTERNAL_ERROR);
180 EVP_MD_CTX_free(hash);
184 static ECDSA_SIG *sm2_sig_gen(const EC_KEY *key, const BIGNUM *e)
186 const BIGNUM *dA = EC_KEY_get0_private_key(key);
187 const EC_GROUP *group = EC_KEY_get0_group(key);
188 const BIGNUM *order = EC_GROUP_get0_order(group);
189 ECDSA_SIG *sig = NULL;
199 kG = EC_POINT_new(group);
201 if (kG == NULL || ctx == NULL) {
202 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
208 rk = BN_CTX_get(ctx);
209 x1 = BN_CTX_get(ctx);
210 tmp = BN_CTX_get(ctx);
212 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
217 * These values are returned and so should not be allocated out of the
223 if (r == NULL || s == NULL) {
224 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
229 if (!BN_priv_rand_range(k, order)) {
230 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_INTERNAL_ERROR);
234 if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
235 || !EC_POINT_get_affine_coordinates(group, kG, x1, NULL,
237 || !BN_mod_add(r, e, x1, order, ctx)) {
238 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_INTERNAL_ERROR);
242 /* try again if r == 0 or r+k == n */
246 if (!BN_add(rk, r, k)) {
247 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_INTERNAL_ERROR);
251 if (BN_cmp(rk, order) == 0)
254 if (!BN_add(s, dA, BN_value_one())
255 || !ec_group_do_inverse_ord(group, s, s, ctx)
256 || !BN_mod_mul(tmp, dA, r, order, ctx)
257 || !BN_sub(tmp, k, tmp)
258 || !BN_mod_mul(s, s, tmp, order, ctx)) {
259 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_BN_LIB);
263 sig = ECDSA_SIG_new();
265 SM2err(SM2_F_SM2_SIG_GEN, ERR_R_MALLOC_FAILURE);
269 /* takes ownership of r and s */
270 ECDSA_SIG_set0(sig, r, s);
285 static int sm2_sig_verify(const EC_KEY *key, const ECDSA_SIG *sig,
289 const EC_GROUP *group = EC_KEY_get0_group(key);
290 const BIGNUM *order = EC_GROUP_get0_order(group);
295 const BIGNUM *r = NULL;
296 const BIGNUM *s = NULL;
299 pt = EC_POINT_new(group);
300 if (ctx == NULL || pt == NULL) {
301 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_MALLOC_FAILURE);
307 x1 = BN_CTX_get(ctx);
309 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_MALLOC_FAILURE);
314 * B1: verify whether r' in [1,n-1], verification failed if not
315 * B2: vefify whether s' in [1,n-1], verification failed if not
316 * B3: set M'~=ZA || M'
317 * B4: calculate e'=Hv(M'~)
318 * B5: calculate t = (r' + s') modn, verification failed if t=0
319 * B6: calculate the point (x1', y1')=[s']G + [t]PA
320 * B7: calculate R=(e'+x1') modn, verfication pass if yes, otherwise failed
323 ECDSA_SIG_get0(sig, &r, &s);
325 if (BN_cmp(r, BN_value_one()) < 0
326 || BN_cmp(s, BN_value_one()) < 0
327 || BN_cmp(order, r) <= 0
328 || BN_cmp(order, s) <= 0) {
329 SM2err(SM2_F_SM2_SIG_VERIFY, SM2_R_BAD_SIGNATURE);
333 if (!BN_mod_add(t, r, s, order, ctx)) {
334 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_BN_LIB);
339 SM2err(SM2_F_SM2_SIG_VERIFY, SM2_R_BAD_SIGNATURE);
343 if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
344 || !EC_POINT_get_affine_coordinates(group, pt, x1, NULL, ctx)) {
345 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_EC_LIB);
349 if (!BN_mod_add(t, e, x1, order, ctx)) {
350 SM2err(SM2_F_SM2_SIG_VERIFY, ERR_R_BN_LIB);
354 if (BN_cmp(r, t) == 0)
363 ECDSA_SIG *sm2_do_sign(const EC_KEY *key,
364 const EVP_MD *digest,
367 const uint8_t *msg, size_t msg_len)
370 ECDSA_SIG *sig = NULL;
372 e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
374 /* SM2err already called */
378 sig = sm2_sig_gen(key, e);
385 int sm2_do_verify(const EC_KEY *key,
386 const EVP_MD *digest,
387 const ECDSA_SIG *sig,
390 const uint8_t *msg, size_t msg_len)
395 e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
397 /* SM2err already called */
401 ret = sm2_sig_verify(key, sig, e);
408 int sm2_sign(const unsigned char *dgst, int dgstlen,
409 unsigned char *sig, unsigned int *siglen, EC_KEY *eckey)
416 e = BN_bin2bn(dgst, dgstlen, NULL);
418 SM2err(SM2_F_SM2_SIGN, ERR_R_BN_LIB);
422 s = sm2_sig_gen(eckey, e);
424 sigleni = i2d_ECDSA_SIG(s, &sig);
426 SM2err(SM2_F_SM2_SIGN, ERR_R_INTERNAL_ERROR);
429 *siglen = (unsigned int)sigleni;
439 int sm2_verify(const unsigned char *dgst, int dgstlen,
440 const unsigned char *sig, int sig_len, EC_KEY *eckey)
444 const unsigned char *p = sig;
445 unsigned char *der = NULL;
451 SM2err(SM2_F_SM2_VERIFY, ERR_R_MALLOC_FAILURE);
454 if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
455 SM2err(SM2_F_SM2_VERIFY, SM2_R_INVALID_ENCODING);
458 /* Ensure signature uses DER and doesn't have trailing garbage */
459 derlen = i2d_ECDSA_SIG(s, &der);
460 if (derlen != sig_len || memcmp(sig, der, derlen) != 0) {
461 SM2err(SM2_F_SM2_VERIFY, SM2_R_INVALID_ENCODING);
465 e = BN_bin2bn(dgst, dgstlen, NULL);
467 SM2err(SM2_F_SM2_VERIFY, ERR_R_BN_LIB);
471 ret = sm2_sig_verify(eckey, s, e);