tomcrypt/pmac_process.c
2010-06-16 12:38:16 +02:00

63 lines
1.7 KiB
C

/* 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@iahu.ca, http://libtomcrypt.org
*/
/* PMAC implementation by Tom St Denis */
#include "mycrypt.h"
#ifdef PMAC
int pmac_process(pmac_state *state, const unsigned char *buf, unsigned long len)
{
int err, n, x;
unsigned char Z[MAXBLOCKSIZE];
_ARGCHK(state != NULL);
_ARGCHK(buf != NULL);
if ((err = cipher_is_valid(state->cipher_idx)) != CRYPT_OK) {
return err;
}
if ((state->buflen > (int)sizeof(state->block)) || (state->buflen < 0) ||
(state->block_len > (int)sizeof(state->block)) || (state->buflen > state->block_len)) {
return CRYPT_INVALID_ARG;
}
while (len != 0) {
/* ok if the block is full we xor in prev, encrypt and replace prev */
if (state->buflen == state->block_len) {
pmac_shift_xor(state);
for (x = 0; x < state->block_len; x++) {
Z[x] = state->Li[x] ^ state->block[x];
}
cipher_descriptor[state->cipher_idx].ecb_encrypt(Z, Z, &state->key);
for (x = 0; x < state->block_len; x++) {
state->checksum[x] ^= Z[x];
}
state->buflen = 0;
}
/* add bytes */
n = MIN(len, (unsigned long)(state->block_len - state->buflen));
XMEMCPY(state->block + state->buflen, buf, n);
state->buflen += n;
len -= n;
buf += n;
}
#ifdef CLEAN_STACK
zeromem(Z, sizeof(Z));
#endif
return CRYPT_OK;
}
#endif