| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| * |
| * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com |
| */ |
| #include "tomcrypt.h" |
| |
| /** |
| @file lrw_setiv.c |
| LRW_MODE implementation, Set the current IV, Tom St Denis |
| */ |
| |
| #ifdef LTC_LRW_MODE |
| |
| /** |
| Set the IV for LRW |
| @param IV The IV, must be 16 octets |
| @param len Length ... must be 16 :-) |
| @param lrw The LRW state to update |
| @return CRYPT_OK if successful |
| */ |
| int lrw_setiv(const unsigned char *IV, unsigned long len, symmetric_LRW *lrw) |
| { |
| int err; |
| #ifdef LRW_TABLES |
| unsigned char T[16]; |
| int x, y; |
| #endif |
| LTC_ARGCHK(IV != NULL); |
| LTC_ARGCHK(lrw != NULL); |
| |
| if (len != 16) { |
| return CRYPT_INVALID_ARG; |
| } |
| |
| if ((err = cipher_is_valid(lrw->cipher)) != CRYPT_OK) { |
| return err; |
| } |
| |
| /* copy the IV */ |
| XMEMCPY(lrw->IV, IV, 16); |
| |
| /* check if we have to actually do work */ |
| if (cipher_descriptor[lrw->cipher].accel_lrw_encrypt != NULL && cipher_descriptor[lrw->cipher].accel_lrw_decrypt != NULL) { |
| /* we have accelerators, let's bail since they don't use lrw->pad anyways */ |
| return CRYPT_OK; |
| } |
| |
| #ifdef LRW_TABLES |
| XMEMCPY(T, &lrw->PC[0][IV[0]][0], 16); |
| for (x = 1; x < 16; x++) { |
| #ifdef LTC_FAST |
| for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) { |
| *((LTC_FAST_TYPE *)(T + y)) ^= *((LTC_FAST_TYPE *)(&lrw->PC[x][IV[x]][y])); |
| } |
| #else |
| for (y = 0; y < 16; y++) { |
| T[y] ^= lrw->PC[x][IV[x]][y]; |
| } |
| #endif |
| } |
| XMEMCPY(lrw->pad, T, 16); |
| #else |
| gcm_gf_mult(lrw->tweak, IV, lrw->pad); |
| #endif |
| |
| return CRYPT_OK; |
| } |
| |
| |
| #endif |
| /* $Source: /cvs/libtom/libtomcrypt/src/modes/lrw/lrw_setiv.c,v $ */ |
| /* $Revision: 1.12 $ */ |
| /* $Date: 2006/06/29 01:53:13 $ */ |