1/*
2 * Copyright 2015-2019 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <string.h>
11#include <openssl/core_names.h>
12#include <openssl/ec.h>
13#include <openssl/evp.h>
14#include <openssl/kdf.h>
15#include "ec_local.h"
16
17/* Key derivation function from X9.63/SECG */
18int ecdh_KDF_X9_63(unsigned char *out, size_t outlen,
19 const unsigned char *Z, size_t Zlen,
20 const unsigned char *sinfo, size_t sinfolen,
21 const EVP_MD *md)
22{
23 int ret = 0;
24 EVP_KDF_CTX *kctx = NULL;
25 OSSL_PARAM params[4], *p = params;
26 const char *mdname = EVP_MD_name(md);
27 EVP_KDF *kdf = EVP_KDF_fetch(NULL, OSSL_KDF_NAME_X963KDF, NULL);
28
29 if ((kctx = EVP_KDF_CTX_new(kdf)) != NULL) {
30 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
31 (char *)mdname,
32 strlen(mdname) + 1);
33 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
34 (void *)Z, Zlen);
35 *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
36 (void *)sinfo, sinfolen);
37 *p = OSSL_PARAM_construct_end();
38
39 ret = EVP_KDF_CTX_set_params(kctx, params) > 0
40 && EVP_KDF_derive(kctx, out, outlen) > 0;
41 EVP_KDF_CTX_free(kctx);
42 }
43 EVP_KDF_free(kdf);
44 return ret;
45}
46
47/*-
48 * The old name for ecdh_KDF_X9_63
49 * Retained for ABI compatibility
50 */
51#ifndef OPENSSL_NO_DEPRECATED_3_0
52int ECDH_KDF_X9_62(unsigned char *out, size_t outlen,
53 const unsigned char *Z, size_t Zlen,
54 const unsigned char *sinfo, size_t sinfolen,
55 const EVP_MD *md)
56{
57 return ecdh_KDF_X9_63(out, outlen, Z, Zlen, sinfo, sinfolen, md);
58}
59#endif
60