pcompress/crypto/sha2/_hmac.c

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2013-03-07 14:56:48 +00:00
/*
* This file is a part of Pcompress, a chunked parallel multi-
* algorithm lossless compression and decompression program.
*
* Copyright (C) 2012-2013 Moinak Ghosh. All rights reserved.
* Use is subject to license terms.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program.
* If not, see <http://www.gnu.org/licenses/>.
*
* moinakg@belenix.org, http://moinakg.wordpress.com/
*
*/
/*-
* Copyright (c) 2010, 2011 Allan Saddi <allan@saddi.com>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS 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 AUTHOR OR 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.
*/
void
HMAC_INIT(HMAC_CONTEXT *ctxt, const void *key, size_t keyLen)
{
HASH_CONTEXT keyCtxt;
unsigned int i;
uint8_t pkey[HASH_BLOCK_SIZE], okey[HASH_BLOCK_SIZE], ikey[HASH_BLOCK_SIZE];
/* Ensure key is zero-padded */
memset(pkey, 0, sizeof(pkey));
if (keyLen > sizeof(pkey)) {
/* Hash key if > HASH_BLOCK_SIZE */
HASH_INIT(&keyCtxt);
HASH_UPDATE(&keyCtxt, key, keyLen);
HASH_FINAL(&keyCtxt, pkey);
}
else {
memcpy(pkey, key, keyLen);
}
/* XOR with opad, ipad */
for (i = 0; i < sizeof(okey); i++) {
okey[i] = pkey[i] ^ 0x5c;
}
for (i = 0; i < sizeof(ikey); i++) {
ikey[i] = pkey[i] ^ 0x36;
}
/* Initialize hash contexts */
HASH_INIT(&ctxt->outer);
HASH_UPDATE(&ctxt->outer, okey, sizeof(okey));
HASH_INIT(&ctxt->inner);
HASH_UPDATE(&ctxt->inner, ikey, sizeof(ikey));
/* Burn the stack */
memset(ikey, 0, sizeof(ikey));
memset(okey, 0, sizeof(okey));
memset(pkey, 0, sizeof(pkey));
memset(&keyCtxt, 0, sizeof(keyCtxt));
}
void
HMAC_UPDATE(HMAC_CONTEXT *ctxt, const void *data, size_t len)
{
HASH_UPDATE(&ctxt->inner, data, len);
}
void
HMAC_FINAL(HMAC_CONTEXT *ctxt, uint8_t hmac[HASH_SIZE])
{
uint8_t ihash[HASH_SIZE];
HASH_FINAL(&ctxt->inner, ihash);
HASH_UPDATE(&ctxt->outer, ihash, sizeof(ihash));
HASH_FINAL(&ctxt->outer, hmac);
memset(ihash, 0, sizeof(ihash));
}