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 omac_process.c
15 OMAC1 support, process data, Tom St Denis
16 */
17
18
19 #ifdef LTC_OMAC
20
21 /**
22 Process data through OMAC
23 @param omac The OMAC state
24 @param in The input data to send through OMAC
25 @param inlen The length of the input (octets)
26 @return CRYPT_OK if successful
27 */
omac_process(omac_state * omac,const unsigned char * in,unsigned long inlen)28 int omac_process(omac_state *omac, const unsigned char *in, unsigned long inlen)
29 {
30 unsigned long n, x;
31 int err;
32
33 LTC_ARGCHK(omac != NULL);
34 LTC_ARGCHK(in != NULL);
35 if ((err = cipher_is_valid(omac->cipher_idx)) != CRYPT_OK) {
36 return err;
37 }
38
39 if ((omac->buflen > (int)sizeof(omac->block)) || (omac->buflen < 0) ||
40 (omac->blklen > (int)sizeof(omac->block)) || (omac->buflen > omac->blklen)) {
41 return CRYPT_INVALID_ARG;
42 }
43
44 #ifdef LTC_FAST
45 if (omac->buflen == 0 && inlen > 16) {
46 int y;
47 for (x = 0; x < (inlen - 16); x += 16) {
48 for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
49 *((LTC_FAST_TYPE*)(&omac->prev[y])) ^= *((LTC_FAST_TYPE*)(&in[y]));
50 }
51 in += 16;
52 if ((err = cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->prev, omac->prev, &omac->key)) != CRYPT_OK) {
53 return err;
54 }
55 }
56 inlen -= x;
57 }
58 #endif
59
60 while (inlen != 0) {
61 /* ok if the block is full we xor in prev, encrypt and replace prev */
62 if (omac->buflen == omac->blklen) {
63 for (x = 0; x < (unsigned long)omac->blklen; x++) {
64 omac->block[x] ^= omac->prev[x];
65 }
66 if ((err = cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->block, omac->prev, &omac->key)) != CRYPT_OK) {
67 return err;
68 }
69 omac->buflen = 0;
70 }
71
72 /* add bytes */
73 n = MIN(inlen, (unsigned long)(omac->blklen - omac->buflen));
74 XMEMCPY(omac->block + omac->buflen, in, n);
75 omac->buflen += n;
76 inlen -= n;
77 in += n;
78 }
79
80 return CRYPT_OK;
81 }
82
83 #endif
84
85
86 /* $Source: /cvs/libtom/libtomcrypt/src/mac/omac/omac_process.c,v $ */
87 /* $Revision: 1.9 $ */
88 /* $Date: 2006/11/03 00:39:49 $ */
89