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/*
* Copyright (c) 2001-2007, Tom St Denis
* 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
*/
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtom.org
*/
#include "tomcrypt.h"
/**
@file hmac_done.c
LTC_HMAC support, terminate stream, Tom St Denis/Dobes Vandermeer
*/
#ifdef LTC_HMAC
#define LTC_HMAC_BLOCKSIZE hash_descriptor[hash]->blocksize
/**
Terminate an LTC_HMAC session
@param hmac The LTC_HMAC state
@param out [out] The destination of the LTC_HMAC authentication tag
@param outlen [in/out] The max size and resulting size of the LTC_HMAC authentication tag
@return CRYPT_OK if successful
*/
int hmac_done(hmac_state *hmac, unsigned char *out, unsigned long *outlen)
{
unsigned char *buf, *isha;
unsigned long hashsize, i;
int hash, err;
LTC_ARGCHK(hmac != NULL);
LTC_ARGCHK(out != NULL);
/* test hash */
hash = hmac->hash;
if((err = hash_is_valid(hash)) != CRYPT_OK) {
return err;
}
/* get the hash message digest size */
hashsize = hash_descriptor[hash]->hashsize;
/* allocate buffers */
buf = XMALLOC(LTC_HMAC_BLOCKSIZE);
isha = XMALLOC(hashsize);
if (buf == NULL || isha == NULL) {
if (buf != NULL) {
XFREE(buf);
}
if (isha != NULL) {
XFREE(isha);
}
return CRYPT_MEM;
}
/* Get the hash of the first LTC_HMAC vector plus the data */
if ((err = hash_descriptor[hash]->done(&hmac->md, isha)) != CRYPT_OK) {
goto LBL_ERR;
}
/* Create the second LTC_HMAC vector vector for step (3) */
for(i=0; i < LTC_HMAC_BLOCKSIZE; i++) {
buf[i] = hmac->key[i] ^ 0x5C;
}
/* Now calculate the "outer" hash for step (5), (6), and (7) */
if ((err = hash_descriptor[hash]->init(&hmac->md)) != CRYPT_OK) {
goto LBL_ERR;
}
if ((err = hash_descriptor[hash]->process(&hmac->md, buf, LTC_HMAC_BLOCKSIZE)) != CRYPT_OK) {
goto LBL_ERR;
}
if ((err = hash_descriptor[hash]->process(&hmac->md, isha, hashsize)) != CRYPT_OK) {
goto LBL_ERR;
}
if ((err = hash_descriptor[hash]->done(&hmac->md, buf)) != CRYPT_OK) {
goto LBL_ERR;
}
/* copy to output */
for (i = 0; i < hashsize && i < *outlen; i++) {
out[i] = buf[i];
}
*outlen = i;
err = CRYPT_OK;
LBL_ERR:
#ifdef LTC_CLEAN_STACK
zeromem(isha, hashsize);
zeromem(buf, hashsize);
zeromem(hmac, sizeof(*hmac));
#endif
XFREE(isha);
XFREE(buf);
return err;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/mac/hmac/hmac_done.c,v $ */
/* $Revision: 1.7 $ */
/* $Date: 2007/05/12 14:37:41 $ */
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