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/*
* Copyright (c) 2001-2007, Tom St Denis
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/* 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
*/
/**
@file ocb_encrypt.c
OCB implementation, encrypt data, by Tom St Denis
*/
#include "tomcrypt.h"
#ifdef LTC_OCB_MODE
/**
Encrypt a block of data with OCB.
@param ocb The OCB state
@param pt The plaintext (length of the block size of the block cipher)
@param ct [out] The ciphertext (same size as the pt)
@return CRYPT_OK if successful
*/
int ocb_encrypt(ocb_state *ocb, const unsigned char *pt, unsigned char *ct)
{
unsigned char Z[MAXBLOCKSIZE], tmp[MAXBLOCKSIZE];
int err, x;
LTC_ARGCHK(ocb != NULL);
LTC_ARGCHK(pt != NULL);
LTC_ARGCHK(ct != NULL);
if ((err = cipher_is_valid(ocb->cipher)) != CRYPT_OK) {
return err;
}
if (ocb->block_len != cipher_descriptor[ocb->cipher].block_length) {
return CRYPT_INVALID_ARG;
}
/* compute checksum */
for (x = 0; x < ocb->block_len; x++) {
ocb->checksum[x] ^= pt[x];
}
/* Get Z[i] value */
ocb_shift_xor(ocb, Z);
/* xor pt in, encrypt, xor Z out */
for (x = 0; x < ocb->block_len; x++) {
tmp[x] = pt[x] ^ Z[x];
}
if ((err = cipher_descriptor[ocb->cipher].ecb_encrypt(tmp, ct, &ocb->key)) != CRYPT_OK) {
return err;
}
for (x = 0; x < ocb->block_len; x++) {
ct[x] ^= Z[x];
}
#ifdef LTC_CLEAN_STACK
zeromem(Z, sizeof(Z));
zeromem(tmp, sizeof(tmp));
#endif
return CRYPT_OK;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_encrypt.c,v $ */
/* $Revision: 1.7 $ */
/* $Date: 2007/05/12 14:32:35 $ */
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