crypto/ec/ecdh_kdf.c

   1 /*
   2  * Copyright 2015-2020 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 */
  24 int 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 {
  29     int ret = 0;
  30     EVP_KDF_CTX *kctx = NULL;
  31     OSSL_PARAM params[4], *p = params;
  32     const char *mdname = EVP_MD_name(md);
  33     EVP_KDF *kdf = EVP_KDF_fetch(NULL, OSSL_KDF_NAME_X963KDF, NULL);
  34
  35     if ((kctx = EVP_KDF_new_ctx(kdf)) != NULL) {
  36         *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
  37                                                 (char *)mdname, 0);
  38         *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
  39                                                  (void *)Z, Zlen);
  40         *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
  41                                                  (void *)sinfo, sinfolen);
  42         *p = OSSL_PARAM_construct_end();
  43
  44         ret = EVP_KDF_set_ctx_params(kctx, params) > 0
  45             && EVP_KDF_derive(kctx, out, outlen) > 0;
  46         EVP_KDF_free_ctx(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
  57 int 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 ecdh_KDF_X9_63(out, outlen, Z, Zlen, sinfo, sinfolen, md);
  63 }
  64 #endif