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/*
* Copyright (c) 1999, 2000, 2002 Virtual Unlimited B.V.
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*!\file hmac.c
* \brief HMAC algorithm.
*
* \see RFC2104 HMAC: Keyed-Hashing for Message Authentication.
* H. Krawczyk, M. Bellare, R. Canetti.
*
* \author Bob Deblier <bob.deblier@pandore.be>
* \ingroup HMAC_m
*/
#include "system.h"
#include "hmac.h"
#include "endianness.h"
#include "debug.h"
/*!\addtogroup HMAC_m
* \{
*/
#define HMAC_IPAD 0x36
#define HMAC_OPAD 0x5c
int hmacSetup(byte* kxi, byte* kxo, const hashFunction* hash, hashFunctionParam* param, const byte* key, size_t keybits)
{
register unsigned int i;
size_t keybytes = keybits >> 3;
/* if the key is too large, hash it first */
if (keybytes > hash->blocksize)
{
/* if the hash digest is too large, this doesn't help; this is really a sanity check */
if (hash->digestsize > hash->blocksize)
return -1;
if (hash->reset(param))
return -1;
if (hash->update(param, key, keybytes))
return -1;
if (hash->digest(param, kxi))
return -1;
memcpy(kxo, kxi, keybytes = hash->digestsize);
}
else if (keybytes > 0)
{
memcpy(kxi, key, keybytes);
memcpy(kxo, key, keybytes);
}
else
return -1;
for (i = 0; i < keybytes; i++)
{
kxi[i] ^= HMAC_IPAD;
kxo[i] ^= HMAC_OPAD;
}
for (i = keybytes; i < hash->blocksize; i++)
{
kxi[i] = HMAC_IPAD;
kxo[i] = HMAC_OPAD;
}
return hmacReset(kxi, hash, param);
}
int hmacReset(const byte* kxi, const hashFunction* hash, hashFunctionParam* param)
{
if (hash->reset(param))
return -1;
if (hash->update(param, kxi, hash->blocksize))
return -1;
return 0;
}
int hmacUpdate(const hashFunction* hash, hashFunctionParam* param, const byte* data, size_t size)
{
return hash->update(param, data, size);
}
int hmacDigest(const byte* kxo, const hashFunction* hash, hashFunctionParam* param, byte* data)
{
if (hash->digest(param, data))
return -1;
if (hash->update(param, kxo, hash->blocksize))
return -1;
if (hash->update(param, data, hash->digestsize))
return -1;
if (hash->digest(param, data))
return -1;
return 0;
}
/*!\}
*/
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