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/*
* Copyright (c) 2001-2007, Tom St Denis
* Copyright (c) 2014, STMicroelectronics International N.V.
* 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"
#ifdef LTC_CCM_MODE
/**
Add AAD to the CCM state
@param ccm The CCM state
@param adata The additional authentication data to add to the CCM state
@param adatalen The length of the AAD data.
@return CRYPT_OK on success
*/
int ccm_add_aad(ccm_state *ccm,
const unsigned char *adata, unsigned long adatalen)
{
unsigned long y;
int err;
LTC_ARGCHK(ccm != NULL);
LTC_ARGCHK(adata != NULL);
if (ccm->aadlen < ccm->current_aadlen + adatalen) {
return CRYPT_INVALID_ARG;
}
ccm->current_aadlen += adatalen;
/* now add the data */
for (y = 0; y < adatalen; y++) {
if (ccm->x == 16) {
/* full block so let's encrypt it */
if ((err = cipher_descriptor[ccm->cipher]->ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
return CRYPT_ERROR;
}
ccm->x = 0;
}
ccm->PAD[ccm->x++] ^= adata[y];
}
/* remainder? */
if (ccm->aadlen == ccm->current_aadlen) {
if (ccm->x != 0) {
if ((err = cipher_descriptor[ccm->cipher]->ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
return CRYPT_ERROR;
}
}
ccm->x = 0;
}
return CRYPT_OK;
}
#endif
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