tomcrypt/pmac_done.c
2010-06-16 12:38:11 +02:00

65 lines
1.6 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_done(pmac_state *state, unsigned char *out, unsigned long *outlen)
{
int err, x;
_ARGCHK(state != NULL);
_ARGCHK(out != 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;
}
/* handle padding. If multiple xor in L/x */
if (state->buflen == state->block_len) {
/* xor Lr against the checksum */
for (x = 0; x < state->block_len; x++) {
state->checksum[x] ^= state->block[x] ^ state->Lr[x];
}
} else {
/* otherwise xor message bytes then the 0x80 byte */
for (x = 0; x < state->buflen; x++) {
state->checksum[x] ^= state->block[x];
}
state->checksum[x] ^= 0x80;
}
/* encrypt it */
cipher_descriptor[state->cipher_idx].ecb_encrypt(state->checksum, state->checksum, &state->key);
/* store it */
for (x = 0; x < state->block_len && x <= (int)*outlen; x++) {
out[x] = state->checksum[x];
}
*outlen = x;
#ifdef CLEAN_STACK
zeromem(state, sizeof(*state));
#endif
return CRYPT_OK;
}
#endif