Files
GmSSL/src/sm3_hmac.c
2024-04-19 21:14:10 +08:00

76 lines
1.8 KiB
C

/*
* Copyright 2014-2023 The GmSSL Project. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
*
* http://www.apache.org/licenses/LICENSE-2.0
*/
#include <string.h>
#include <gmssl/sm3.h>
#include <gmssl/error.h>
/**
* HMAC_k(m) = H((k ^ opad) || H((k ^ ipad) || m))
* pseudo-code:
* function hmac(key, message)
* opad = [0x5c * blocksize]
* ipad = [0x36 * blocksize]
* if (length(key) > blocksize) then
* key = hash(key)
* end if
* for i from 0 to length(key) - 1 step 1
* ipad[i] = ipad[i] XOR key[i]
* opad[i] = opad[i] XOR key[i]
* end for
* return hash(opad || hash(ipad || message))
* end function
*/
#define IPAD 0x36
#define OPAD 0x5C
void sm3_hmac_init(SM3_HMAC_CTX *ctx, const uint8_t *key, size_t key_len)
{
int i;
if (key_len <= SM3_BLOCK_SIZE) {
memcpy(ctx->key, key, key_len);
memset(ctx->key + key_len, 0, SM3_BLOCK_SIZE - key_len);
} else {
sm3_init(&ctx->sm3_ctx);
sm3_update(&ctx->sm3_ctx, key, key_len);
sm3_finish(&ctx->sm3_ctx, ctx->key);
memset(ctx->key + SM3_DIGEST_SIZE, 0,
SM3_BLOCK_SIZE - SM3_DIGEST_SIZE);
}
for (i = 0; i < SM3_BLOCK_SIZE; i++) {
ctx->key[i] ^= IPAD;
}
sm3_init(&ctx->sm3_ctx);
sm3_update(&ctx->sm3_ctx, ctx->key, SM3_BLOCK_SIZE);
}
void sm3_hmac_update(SM3_HMAC_CTX *ctx, const uint8_t *data, size_t data_len)
{
sm3_update(&ctx->sm3_ctx, data, data_len);
}
void sm3_hmac_finish(SM3_HMAC_CTX *ctx, uint8_t mac[SM3_HMAC_SIZE])
{
int i;
for (i = 0; i < SM3_BLOCK_SIZE; i++) {
ctx->key[i] ^= (IPAD ^ OPAD);
}
sm3_finish(&ctx->sm3_ctx, mac);
sm3_init(&ctx->sm3_ctx);
sm3_update(&ctx->sm3_ctx, ctx->key, SM3_BLOCK_SIZE);
sm3_update(&ctx->sm3_ctx, mac, SM3_DIGEST_SIZE);
sm3_finish(&ctx->sm3_ctx, mac);
}