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/* 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 omac_process.c
LTC_OMAC1 support, process data, Tom St Denis
*/
#ifdef LTC_OMAC
/**
Process data through LTC_OMAC
@param omac The LTC_OMAC state
@param in The input data to send through LTC_OMAC
@param inlen The length of the input (octets)
@return CRYPT_OK if successful
*/
int omac_process(omac_state *omac, const unsigned char *in, unsigned long inlen)
{
unsigned long n, x;
int err;
LTC_ARGCHK(omac != NULL);
LTC_ARGCHK(in != NULL);
if ((err = cipher_is_valid(omac->cipher_idx)) != CRYPT_OK) {
return err;
}
if ((omac->buflen > (int)sizeof(omac->block)) || (omac->buflen < 0) ||
(omac->blklen > (int)sizeof(omac->block)) || (omac->buflen > omac->blklen)) {
return CRYPT_INVALID_ARG;
}
#ifdef LTC_FAST
{
unsigned long blklen;
blklen = cipher_descriptor[omac->cipher_idx].block_length;
if (omac->buflen == 0 && inlen > blklen) {
unsigned long y;
for (x = 0; x < (inlen - blklen); x += blklen) {
for (y = 0; y < blklen; y += sizeof(LTC_FAST_TYPE)) {
*((LTC_FAST_TYPE*)(&omac->prev[y])) ^= *((LTC_FAST_TYPE*)(&in[y]));
}
in += blklen;
if ((err = cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->prev, omac->prev, &omac->key)) != CRYPT_OK) {
return err;
}
}
inlen -= x;
}
}
#endif
while (inlen != 0) {
/* ok if the block is full we xor in prev, encrypt and replace prev */
if (omac->buflen == omac->blklen) {
for (x = 0; x < (unsigned long)omac->blklen; x++) {
omac->block[x] ^= omac->prev[x];
}
if ((err = cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->block, omac->prev, &omac->key)) != CRYPT_OK) {
return err;
}
omac->buflen = 0;
}
/* add bytes */
n = MIN(inlen, (unsigned long)(omac->blklen - omac->buflen));
XMEMCPY(omac->block + omac->buflen, in, n);
omac->buflen += n;
inlen -= n;
in += n;
}
return CRYPT_OK;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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