/*

 * Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*

 * ECDH low level APIs are deprecated for public use, but still ok for

 * internal use.

 */

#include "internal/deprecated.h"

#include <string.h>

#include <openssl/core_names.h>

#include <openssl/ec.h>

#include <openssl/evp.h>

#include <openssl/kdf.h>

#include "ec_local.h"

/* Key derivation function from X9.63/SECG */

int ossl_ecdh_kdf_X9_63(unsigned char *out, size_t outlen,

                        const unsigned char *Z, size_t Zlen,

                        const unsigned char *sinfo, size_t sinfolen,

                        const EVP_MD *md,

                        OSSL_LIB_CTX *libctx, const char *propq)

{

    int ret = 0;

    EVP_KDF_CTX *kctx = NULL;

    OSSL_PARAM params[4], *p = params;

    const char *mdname = EVP_MD_get0_name(md);

    EVP_KDF *kdf = EVP_KDF_fetch(libctx, OSSL_KDF_NAME_X963KDF, propq);

    if ((kctx = EVP_KDF_CTX_new(kdf)) != NULL) {

        *p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,

                                                (char *)mdname, 0);

        *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,

                                                 (void *)Z, Zlen);

        *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,

                                                 (void *)sinfo, sinfolen);

        *p = OSSL_PARAM_construct_end();

        ret = EVP_KDF_derive(kctx, out, outlen, params) > 0;

        EVP_KDF_CTX_free(kctx);

    }

    EVP_KDF_free(kdf);

    return ret;

}

/*-

 * The old name for ecdh_KDF_X9_63

 * Retained for ABI compatibility

 */

#ifndef OPENSSL_NO_DEPRECATED_3_0

int ECDH_KDF_X9_62(unsigned char *out, size_t outlen,

                   const unsigned char *Z, size_t Zlen,

                   const unsigned char *sinfo, size_t sinfolen,

                   const EVP_MD *md)

{

    return ossl_ecdh_kdf_X9_63(out, outlen, Z, Zlen, sinfo, sinfolen, md, NULL,

                               NULL);

}

#endif