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/*
* Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
* Copyright 2017 Ribose Inc. All Rights Reserved.
* Ported from Ribose contributions from Botan.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/sm2.h"
#include "internal/sm2err.h"
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/bn.h>
#include <string.h>
#include "internal/numbers.h"
int sm2_compute_userid_digest(uint8_t *out,
const EVP_MD *digest,
const char *user_id,
const EC_KEY *key)
{
int rc = 0;
const EC_GROUP *group = EC_KEY_get0_group(key);
BN_CTX *ctx = NULL;
EVP_MD_CTX *hash = NULL;
BIGNUM *p = NULL;
BIGNUM *a = NULL;
BIGNUM *b = NULL;
BIGNUM *xG = NULL;
BIGNUM *yG = NULL;
BIGNUM *xA = NULL;
BIGNUM *yA = NULL;
int p_bytes = 0;
uint8_t *buf = NULL;
size_t uid_len = 0;
uint16_t entla = 0;
uint8_t e_byte = 0;
hash = EVP_MD_CTX_new();
ctx = BN_CTX_new();
if (hash == NULL || ctx == NULL) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_MALLOC_FAILURE);
goto done;
}
p = BN_CTX_get(ctx);
a = BN_CTX_get(ctx);
b = BN_CTX_get(ctx);
xG = BN_CTX_get(ctx);
yG = BN_CTX_get(ctx);
xA = BN_CTX_get(ctx);
yA = BN_CTX_get(ctx);
if (yA == NULL) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_MALLOC_FAILURE);
goto done;
}
if (!EVP_DigestInit(hash, digest)) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_EVP_LIB);
goto done;
}
/* ZA = H256(ENTLA || IDA || a || b || xG || yG || xA || yA) */
uid_len = strlen(user_id);
if (uid_len >= (UINT16_MAX / 8)) {
/* too large */
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, SM2_R_USER_ID_TOO_LARGE);
goto done;
}
entla = (uint16_t)(8 * uid_len);
e_byte = entla >> 8;
if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_EVP_LIB);
goto done;
}
e_byte = entla & 0xFF;
if (!EVP_DigestUpdate(hash, &e_byte, 1)
|| !EVP_DigestUpdate(hash, user_id, uid_len)) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_EVP_LIB);
goto done;
}
if (!EC_GROUP_get_curve_GFp(group, p, a, b, ctx)) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_EC_LIB);
goto done;
}
p_bytes = BN_num_bytes(p);
buf = OPENSSL_zalloc(p_bytes);
if (buf == NULL) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_MALLOC_FAILURE);
goto done;
}
if (BN_bn2binpad(a, buf, p_bytes) < 0
|| !EVP_DigestUpdate(hash, buf, p_bytes)
|| BN_bn2binpad(b, buf, p_bytes) < 0
|| !EVP_DigestUpdate(hash, buf, p_bytes)
|| !EC_POINT_get_affine_coordinates_GFp(group,
EC_GROUP_get0_generator(group),
xG, yG, ctx)
|| BN_bn2binpad(xG, buf, p_bytes) < 0
|| !EVP_DigestUpdate(hash, buf, p_bytes)
|| BN_bn2binpad(yG, buf, p_bytes) < 0
|| !EVP_DigestUpdate(hash, buf, p_bytes)
|| !EC_POINT_get_affine_coordinates_GFp(group,
EC_KEY_get0_public_key(key),
xA, yA, ctx)
|| BN_bn2binpad(xA, buf, p_bytes) < 0
|| !EVP_DigestUpdate(hash, buf, p_bytes)
|| BN_bn2binpad(yA, buf, p_bytes) < 0
|| !EVP_DigestUpdate(hash, buf, p_bytes)
|| !EVP_DigestFinal(hash, out, NULL)) {
SM2err(SM2_F_SM2_COMPUTE_USERID_DIGEST, ERR_R_INTERNAL_ERROR);
goto done;
}
rc = 1;
done:
OPENSSL_free(buf);
BN_CTX_free(ctx);
EVP_MD_CTX_free(hash);
return rc;
}
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