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comparison src/modes/ofb/ofb_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 ofb_encrypt.c
15 OFB implementation, encrypt data, Tom St Denis
16 */
17
18 #ifdef OFB
19
20 /**
21 OFB encrypt
22 @param pt Plaintext
23 @param ct [out] Ciphertext
24 @param len Length of plaintext (octets)
25 @param ofb OFB state
26 @return CRYPT_OK if successful
27 */
28 int ofb_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_OFB *ofb)
29 {
30 int err;
31 LTC_ARGCHK(pt != NULL);
32 LTC_ARGCHK(ct != NULL);
33 LTC_ARGCHK(ofb != NULL);
34 if ((err = cipher_is_valid(ofb->cipher)) != CRYPT_OK) {
35 return err;
36 }
37
38 /* is blocklen/padlen valid? */
39 if (ofb->blocklen < 0 || ofb->blocklen > (int)sizeof(ofb->IV) ||
40 ofb->padlen < 0 || ofb->padlen > (int)sizeof(ofb->IV)) {
41 return CRYPT_INVALID_ARG;
42 }
43
44 while (len-- > 0) {
45 if (ofb->padlen == ofb->blocklen) {
46 cipher_descriptor[ofb->cipher].ecb_encrypt(ofb->IV, ofb->IV, &ofb->key);
47 ofb->padlen = 0;
48 }
49 *ct++ = *pt++ ^ ofb->IV[ofb->padlen++];
50 }
51 return CRYPT_OK;
52 }
53
54 #endif