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/* 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://libtom.org
*/
#include "tomcrypt.h"
/**
Source donated by Elliptic Semiconductor Inc (www.ellipticsemi.com) to the LibTom Projects
*/
#ifdef LTC_XTS_MODE
/** Start XTS mode
@param cipher The index of the cipher to use
@param key1 The encrypt key
@param key2 The tweak encrypt key
@param keylen The length of the keys (each) in octets
@param num_rounds The number of rounds for the cipher (0 == default)
@param xts [out] XTS structure
Returns CRYPT_OK upon success.
*/
int xts_start( int cipher,
const unsigned char *key1,
const unsigned char *key2,
unsigned long keylen,
int num_rounds,
symmetric_xts *xts)
{
int err;
/* check inputs */
LTC_ARGCHK(key1 != NULL);
LTC_ARGCHK(key2 != NULL);
LTC_ARGCHK(xts != NULL);
/* check if valid */
if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
return err;
}
if (cipher_descriptor[cipher].block_length != 16) {
return CRYPT_INVALID_ARG;
}
/* schedule the two ciphers */
if ((err = cipher_descriptor[cipher].setup(key1, keylen, num_rounds, &xts->key1)) != CRYPT_OK) {
return err;
}
if ((err = cipher_descriptor[cipher].setup(key2, keylen, num_rounds, &xts->key2)) != CRYPT_OK) {
return err;
}
xts->cipher = cipher;
return err;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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