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 xcbc_process.c
15  XCBC Support, process blocks with XCBC
16*/
17
18#ifdef LTC_XCBC
19
20/** Process data through XCBC-MAC
21  @param xcbc     The XCBC-MAC state
22  @param in       Input data to process
23  @param inlen    Length of input in octets
24  Return CRYPT_OK on success
25*/
26int xcbc_process(xcbc_state *xcbc, const unsigned char *in, unsigned long inlen)
27{
28   int err;
29#ifdef LTC_FAST
30   int x;
31#endif
32
33   LTC_ARGCHK(xcbc != NULL);
34   LTC_ARGCHK(in   != NULL);
35
36   /* check structure */
37   if ((err = cipher_is_valid(xcbc->cipher)) != CRYPT_OK) {
38      return err;
39   }
40
41   if ((xcbc->blocksize > cipher_descriptor[xcbc->cipher].block_length) || (xcbc->blocksize < 0) ||
42       (xcbc->buflen > xcbc->blocksize) || (xcbc->buflen < 0)) {
43      return CRYPT_INVALID_ARG;
44   }
45
46#ifdef LTC_FAST
47   if (xcbc->buflen == 0) {
48       while (inlen > (unsigned long)xcbc->blocksize) {
49           for (x = 0; x < xcbc->blocksize; x += sizeof(LTC_FAST_TYPE)) {
50              *((LTC_FAST_TYPE*)&(xcbc->IV[x])) ^= *((LTC_FAST_TYPE*)&(in[x]));
51           }
52           cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key);
53           in    += xcbc->blocksize;
54           inlen -= xcbc->blocksize;
55       }
56  }
57#endif
58
59   while (inlen) {
60     if (xcbc->buflen == xcbc->blocksize) {
61         cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key);
62         xcbc->buflen = 0;
63     }
64     xcbc->IV[xcbc->buflen++] ^= *in++;
65     --inlen;
66  }
67  return CRYPT_OK;
68}
69
70#endif
71
72/* $Source: /cvs/libtom/libtomcrypt/src/mac/xcbc/xcbc_process.c,v $ */
73/* $Revision: 1.9 $ */
74/* $Date: 2006/11/09 22:43:52 $ */
75
76