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comparison src/modes/f8/f8_encrypt.c @ 380:d5faf4814ddb libtomcrypt-orig libtomcrypt-1.16

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Update to LibTomCrypt 1.16
author Matt Johnston <matt@ucc.asn.au>
date Thu, 11 Jan 2007 02:22:00 +0000
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280:59400faa4b44 380:d5faf4814ddb
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.com
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file f8_encrypt.c
15 F8 implementation, encrypt data, Tom St Denis
16 */
17
18 #ifdef LTC_F8_MODE
19
20 /**
21 F8 encrypt
22 @param pt Plaintext
23 @param ct [out] Ciphertext
24 @param len Length of plaintext (octets)
25 @param f8 F8 state
26 @return CRYPT_OK if successful
27 */
28 int f8_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_F8 *f8)
29 {
30 int err, x;
31 unsigned char buf[MAXBLOCKSIZE];
32 LTC_ARGCHK(pt != NULL);
33 LTC_ARGCHK(ct != NULL);
34 LTC_ARGCHK(f8 != NULL);
35 if ((err = cipher_is_valid(f8->cipher)) != CRYPT_OK) {
36 return err;
37 }
38
39 /* is blocklen/padlen valid? */
40 if (f8->blocklen < 0 || f8->blocklen > (int)sizeof(f8->IV) ||
41 f8->padlen < 0 || f8->padlen > (int)sizeof(f8->IV)) {
42 return CRYPT_INVALID_ARG;
43 }
44
45 zeromem(buf, sizeof(buf));
46
47 /* make sure the pad is empty */
48 if (f8->padlen == f8->blocklen) {
49 /* xor of IV, MIV and blockcnt == what goes into cipher */
50 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
51 ++(f8->blockcnt);
52 for (x = 0; x < f8->blocklen; x++) {
53 f8->IV[x] ^= f8->MIV[x] ^ buf[x];
54 }
55 if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
56 return err;
57 }
58 f8->padlen = 0;
59 }
60
61 #ifdef LTC_FAST
62 if (f8->padlen == 0) {
63 while (len >= (unsigned long)f8->blocklen) {
64 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
65 ++(f8->blockcnt);
66 for (x = 0; x < f8->blocklen; x += sizeof(LTC_FAST_TYPE)) {
67 *((LTC_FAST_TYPE*)(&ct[x])) = *((LTC_FAST_TYPE*)(&pt[x])) ^ *((LTC_FAST_TYPE*)(&f8->IV[x]));
68 *((LTC_FAST_TYPE*)(&f8->IV[x])) ^= *((LTC_FAST_TYPE*)(&f8->MIV[x])) ^ *((LTC_FAST_TYPE*)(&buf[x]));
69 }
70 if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
71 return err;
72 }
73 len -= x;
74 pt += x;
75 ct += x;
76 }
77 }
78 #endif
79
80 while (len > 0) {
81 if (f8->padlen == f8->blocklen) {
82 /* xor of IV, MIV and blockcnt == what goes into cipher */
83 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
84 ++(f8->blockcnt);
85 for (x = 0; x < f8->blocklen; x++) {
86 f8->IV[x] ^= f8->MIV[x] ^ buf[x];
87 }
88 if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
89 return err;
90 }
91 f8->padlen = 0;
92 }
93 *ct++ = *pt++ ^ f8->IV[f8->padlen++];
94 --len;
95 }
96 return CRYPT_OK;
97 }
98
99 #endif
100
101 /* $Source: /cvs/libtom/libtomcrypt/src/modes/f8/f8_encrypt.c,v $ */
102 /* $Revision: 1.6 $ */
103 /* $Date: 2006/11/05 04:16:32 $ */