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comparison src/modes/cbc/cbc_encrypt.c @ 191:1c15b283127b libtomcrypt-orig

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Import of libtomcrypt 1.02 with manual path rename rearrangement etc
author Matt Johnston <matt@ucc.asn.au>
date Fri, 06 May 2005 13:23:02 +0000
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children 39d5d58461d6
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143:5d99163f7e32 191:1c15b283127b
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, [email protected], http://libtomcrypt.org
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file cbc_encrypt.c
15 CBC implementation, encrypt block, Tom St Denis
16 */
17
18
19 #ifdef CBC
20
21 /**
22 CBC encrypt
23 @param pt Plaintext
24 @param ct [out] Ciphertext
25 @param len The number of bytes to process (must be multiple of block length)
26 @param cbc CBC state
27 @return CRYPT_OK if successful
28 */
29 int cbc_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_CBC *cbc)
30 {
31 int x, err;
32
33 LTC_ARGCHK(pt != NULL);
34 LTC_ARGCHK(ct != NULL);
35 LTC_ARGCHK(cbc != NULL);
36
37 if ((err = cipher_is_valid(cbc->cipher)) != CRYPT_OK) {
38 return err;
39 }
40
41 /* is blocklen valid? */
42 if (cbc->blocklen < 0 || cbc->blocklen > (int)sizeof(cbc->IV)) {
43 return CRYPT_INVALID_ARG;
44 }
45
46 if (len % cbc->blocklen) {
47 return CRYPT_INVALID_ARG;
48 }
49 #ifdef LTC_FAST
50 if (len % sizeof(LTC_FAST_TYPE)) {
51 return CRYPT_INVALID_ARG;
52 }
53 #endif
54
55 if (cipher_descriptor[cbc->cipher].accel_cbc_encrypt != NULL) {
56 cipher_descriptor[cbc->cipher].accel_cbc_encrypt(pt, ct, len / cbc->blocklen, cbc->IV, &cbc->key);
57 } else {
58 while (len) {
59 /* xor IV against plaintext */
60 #if defined(LTC_FAST)
61 for (x = 0; x < cbc->blocklen; x += sizeof(LTC_FAST_TYPE)) {
62 *((LTC_FAST_TYPE*)((unsigned char *)cbc->IV + x)) ^= *((LTC_FAST_TYPE*)((unsigned char *)pt + x));
63 }
64 #else
65 for (x = 0; x < cbc->blocklen; x++) {
66 cbc->IV[x] ^= pt[x];
67 }
68 #endif
69
70 /* encrypt */
71 cipher_descriptor[cbc->cipher].ecb_encrypt(cbc->IV, ct, &cbc->key);
72
73 /* store IV [ciphertext] for a future block */
74 #if defined(LTC_FAST)
75 for (x = 0; x < cbc->blocklen; x += sizeof(LTC_FAST_TYPE)) {
76 *((LTC_FAST_TYPE*)((unsigned char *)cbc->IV + x)) = *((LTC_FAST_TYPE*)((unsigned char *)ct + x));
77 }
78 #else
79 for (x = 0; x < cbc->blocklen; x++) {
80 cbc->IV[x] = ct[x];
81 }
82 #endif
83
84 ct += cbc->blocklen;
85 pt += cbc->blocklen;
86 len -= cbc->blocklen;
87 }
88 }
89 return CRYPT_OK;
90 }
91
92 #endif