1/*
2 * Copyright 2015-2021 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/*
11 * ECDH low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14#include "internal/deprecated.h"
15
16#include <string.h>
17#include <openssl/core_names.h>
18#include <openssl/ec.h>
19#include <openssl/evp.h>
20#include <openssl/kdf.h>
21#include "ec_local.h"
22
23/* Key derivation function from X9.63/SECG */
24int ossl_ecdh_kdf_X9_63(unsigned char *out, size_t outlen,
25                        const unsigned char *Z, size_t Zlen,
26                        const unsigned char *sinfo, size_t sinfolen,
27                        const EVP_MD *md,
28                        OSSL_LIB_CTX *libctx, const char *propq)
29{
30    int ret = 0;
31    EVP_KDF_CTX *kctx = NULL;
32    OSSL_PARAM params[4], *p = params;
33    const char *mdname = EVP_MD_get0_name(md);
34    EVP_KDF *kdf = EVP_KDF_fetch(libctx, OSSL_KDF_NAME_X963KDF, propq);
35
36    if ((kctx = EVP_KDF_CTX_new(kdf)) != NULL) {
37        *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
38                                                (char *)mdname, 0);
39        *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
40                                                 (void *)Z, Zlen);
41        *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
42                                                 (void *)sinfo, sinfolen);
43        *p = OSSL_PARAM_construct_end();
44
45        ret = EVP_KDF_derive(kctx, out, outlen, params) > 0;
46        EVP_KDF_CTX_free(kctx);
47    }
48    EVP_KDF_free(kdf);
49    return ret;
50}
51
52/*-
53 * The old name for ecdh_KDF_X9_63
54 * Retained for ABI compatibility
55 */
56#ifndef OPENSSL_NO_DEPRECATED_3_0
57int ECDH_KDF_X9_62(unsigned char *out, size_t outlen,
58                   const unsigned char *Z, size_t Zlen,
59                   const unsigned char *sinfo, size_t sinfolen,
60                   const EVP_MD *md)
61{
62    return ossl_ecdh_kdf_X9_63(out, outlen, Z, Zlen, sinfo, sinfolen, md, NULL,
63                               NULL);
64}
65#endif
66