Mercurial > dropbear
diff src/modes/lrw/lrw_setiv.c @ 380:d5faf4814ddb libtomcrypt-orig libtomcrypt-1.16
Update to LibTomCrypt 1.16
author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 11 Jan 2007 02:22:00 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/modes/lrw/lrw_setiv.c Thu Jan 11 02:22:00 2007 +0000 @@ -0,0 +1,79 @@ +/* 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, [email protected], 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 $ */