1/* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11#include "tomcrypt.h"
12
13/**
14  @file pmac_done.c
15  PMAC implementation, terminate a session, by Tom St Denis
16*/
17
18#ifdef LTC_PMAC
19
20int pmac_done(pmac_state *state, unsigned char *out, unsigned long *outlen)
21{
22   int err, x;
23
24   LTC_ARGCHK(state != NULL);
25   LTC_ARGCHK(out   != NULL);
26   if ((err = cipher_is_valid(state->cipher_idx)) != CRYPT_OK) {
27      return err;
28   }
29
30   if ((state->buflen > (int)sizeof(state->block)) || (state->buflen < 0) ||
31       (state->block_len > (int)sizeof(state->block)) || (state->buflen > state->block_len)) {
32      return CRYPT_INVALID_ARG;
33   }
34
35
36   /* handle padding.  If multiple xor in L/x */
37
38   if (state->buflen == state->block_len) {
39      /* xor Lr against the checksum */
40      for (x = 0; x < state->block_len; x++) {
41          state->checksum[x] ^= state->block[x] ^ state->Lr[x];
42      }
43   } else {
44      /* otherwise xor message bytes then the 0x80 byte */
45      for (x = 0; x < state->buflen; x++) {
46          state->checksum[x] ^= state->block[x];
47      }
48      state->checksum[x] ^= 0x80;
49   }
50
51   /* encrypt it */
52   if ((err = cipher_descriptor[state->cipher_idx].ecb_encrypt(state->checksum, state->checksum, &state->key)) != CRYPT_OK) {
53      return err;
54   }
55   cipher_descriptor[state->cipher_idx].done(&state->key);
56
57   /* store it */
58   for (x = 0; x < state->block_len && x < (int)*outlen; x++) {
59       out[x] = state->checksum[x];
60   }
61   *outlen = x;
62
63#ifdef LTC_CLEAN_STACK
64   zeromem(state, sizeof(*state));
65#endif
66   return CRYPT_OK;
67}
68
69#endif
70
71
72/* $Source: /cvs/libtom/libtomcrypt/src/mac/pmac/pmac_done.c,v $ */
73/* $Revision: 1.8 $ */
74/* $Date: 2006/11/03 00:39:49 $ */
75