109 lines
4.1 KiB
C
109 lines
4.1 KiB
C
/* crypto/ecdh/ec_kdf.c */
|
|
/*
|
|
* Written by Stephen Henson for the OpenSSL project.
|
|
*/
|
|
/* ====================================================================
|
|
* Copyright (c) 2013 The OpenSSL Project. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
*
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* 3. All advertising materials mentioning features or use of this
|
|
* software must display the following acknowledgment:
|
|
* "This product includes software developed by the OpenSSL Project
|
|
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
|
|
*
|
|
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
|
|
* endorse or promote products derived from this software without
|
|
* prior written permission. For written permission, please contact
|
|
* openssl-core@openssl.org.
|
|
*
|
|
* 5. Products derived from this software may not be called "OpenSSL"
|
|
* nor may "OpenSSL" appear in their names without prior written
|
|
* permission of the OpenSSL Project.
|
|
*
|
|
* 6. Redistributions of any form whatsoever must retain the following
|
|
* acknowledgment:
|
|
* "This product includes software developed by the OpenSSL Project
|
|
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
|
|
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
|
|
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
|
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
|
|
* OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
* ====================================================================
|
|
*/
|
|
|
|
#include <string.h>
|
|
#include <openssl/ecdh.h>
|
|
#include <openssl/evp.h>
|
|
|
|
/* Key derivation function from X9.62/SECG */
|
|
/* Way more than we will ever need */
|
|
#define ECDH_KDF_MAX (1 << 30)
|
|
|
|
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)
|
|
{
|
|
EVP_MD_CTX mctx;
|
|
int rv = 0;
|
|
unsigned int i;
|
|
size_t mdlen;
|
|
unsigned char ctr[4];
|
|
if (sinfolen > ECDH_KDF_MAX || outlen > ECDH_KDF_MAX
|
|
|| Zlen > ECDH_KDF_MAX)
|
|
return 0;
|
|
mdlen = EVP_MD_size(md);
|
|
EVP_MD_CTX_init(&mctx);
|
|
for (i = 1;; i++) {
|
|
unsigned char mtmp[EVP_MAX_MD_SIZE];
|
|
EVP_DigestInit_ex(&mctx, md, NULL);
|
|
ctr[3] = i & 0xFF;
|
|
ctr[2] = (i >> 8) & 0xFF;
|
|
ctr[1] = (i >> 16) & 0xFF;
|
|
ctr[0] = (i >> 24) & 0xFF;
|
|
if (!EVP_DigestUpdate(&mctx, Z, Zlen))
|
|
goto err;
|
|
if (!EVP_DigestUpdate(&mctx, ctr, sizeof(ctr)))
|
|
goto err;
|
|
if (!EVP_DigestUpdate(&mctx, sinfo, sinfolen))
|
|
goto err;
|
|
if (outlen >= mdlen) {
|
|
if (!EVP_DigestFinal(&mctx, out, NULL))
|
|
goto err;
|
|
outlen -= mdlen;
|
|
if (outlen == 0)
|
|
break;
|
|
out += mdlen;
|
|
} else {
|
|
if (!EVP_DigestFinal(&mctx, mtmp, NULL))
|
|
goto err;
|
|
memcpy(out, mtmp, outlen);
|
|
OPENSSL_cleanse(mtmp, mdlen);
|
|
break;
|
|
}
|
|
}
|
|
rv = 1;
|
|
err:
|
|
EVP_MD_CTX_cleanup(&mctx);
|
|
return rv;
|
|
}
|