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comparison src/modes/lrw/lrw_setiv.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 lrw_setiv.c
15 LRW_MODE implementation, Set the current IV, Tom St Denis
16 */
17
18 #ifdef LTC_LRW_MODE
19
20 /**
21 Set the IV for LRW
22 @param IV The IV, must be 16 octets
23 @param len Length ... must be 16 :-)
24 @param lrw The LRW state to update
25 @return CRYPT_OK if successful
26 */
27 int lrw_setiv(const unsigned char *IV, unsigned long len, symmetric_LRW *lrw)
28 {
29 int err;
30 #ifdef LRW_TABLES
31 unsigned char T[16];
32 int x, y;
33 #endif
34 LTC_ARGCHK(IV != NULL);
35 LTC_ARGCHK(lrw != NULL);
36
37 if (len != 16) {
38 return CRYPT_INVALID_ARG;
39 }
40
41 if ((err = cipher_is_valid(lrw->cipher)) != CRYPT_OK) {
42 return err;
43 }
44
45 /* copy the IV */
46 XMEMCPY(lrw->IV, IV, 16);
47
48 /* check if we have to actually do work */
49 if (cipher_descriptor[lrw->cipher].accel_lrw_encrypt != NULL && cipher_descriptor[lrw->cipher].accel_lrw_decrypt != NULL) {
50 /* we have accelerators, let's bail since they don't use lrw->pad anyways */
51 return CRYPT_OK;
52 }
53
54 #ifdef LRW_TABLES
55 XMEMCPY(T, &lrw->PC[0][IV[0]][0], 16);
56 for (x = 1; x < 16; x++) {
57 #ifdef LTC_FAST
58 for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
59 *((LTC_FAST_TYPE *)(T + y)) ^= *((LTC_FAST_TYPE *)(&lrw->PC[x][IV[x]][y]));
60 }
61 #else
62 for (y = 0; y < 16; y++) {
63 T[y] ^= lrw->PC[x][IV[x]][y];
64 }
65 #endif
66 }
67 XMEMCPY(lrw->pad, T, 16);
68 #else
69 gcm_gf_mult(lrw->tweak, IV, lrw->pad);
70 #endif
71
72 return CRYPT_OK;
73 }
74
75
76 #endif
77 /* $Source: /cvs/libtom/libtomcrypt/src/modes/lrw/lrw_setiv.c,v $ */
78 /* $Revision: 1.12 $ */
79 /* $Date: 2006/06/29 01:53:13 $ */