1 /*
2 * Copyright 2014-2022 The GmSSL Project. All Rights Reserved.
3 *
4 * Licensed under the Apache License, Version 2.0 (the License); you may
5 * not use this file except in compliance with the License.
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 */
9
10
11
12 #include <string.h>
13 #include <gmssl/sm3.h>
14 #include <gmssl/endian.h>
15 #include <gmssl/error.h>
16
17
sm3_kdf_init(SM3_KDF_CTX * ctx,size_t outlen)18 void sm3_kdf_init(SM3_KDF_CTX *ctx, size_t outlen)
19 {
20 sm3_init(&ctx->sm3_ctx);
21 ctx->outlen = outlen;
22 }
23
sm3_kdf_update(SM3_KDF_CTX * ctx,const uint8_t * data,size_t datalen)24 void sm3_kdf_update(SM3_KDF_CTX *ctx, const uint8_t *data, size_t datalen)
25 {
26 sm3_update(&ctx->sm3_ctx, data, datalen);
27 }
28
sm3_kdf_finish(SM3_KDF_CTX * ctx,uint8_t * out)29 void sm3_kdf_finish(SM3_KDF_CTX *ctx, uint8_t *out)
30 {
31 SM3_CTX sm3_ctx;
32 size_t outlen = ctx->outlen;
33 uint8_t counter_be[4];
34 uint8_t dgst[SM3_DIGEST_SIZE];
35 uint32_t counter = 1;
36 size_t len;
37
38 while (outlen) {
39 PUTU32(counter_be, counter);
40 counter++;
41
42 sm3_ctx = ctx->sm3_ctx;
43 sm3_update(&sm3_ctx, counter_be, sizeof(counter_be));
44 sm3_finish(&sm3_ctx, dgst);
45
46 len = outlen < SM3_DIGEST_SIZE ? outlen : SM3_DIGEST_SIZE;
47 memcpy(out, dgst, len);
48 out += len;
49 outlen -= len;
50 }
51
52 memset(&sm3_ctx, 0, sizeof(SM3_CTX));
53 memset(dgst, 0, sizeof(dgst));
54 }
55