/*
 * Twofish for CryptoAPI
 *
 * Originaly Twofish for GPG
 * By Matthew Skala <mskala@ansuz.sooke.bc.ca>, July 26, 1998
 * 256-bit key length added March 20, 1999
 * Some modifications to reduce the text size by Werner Koch, April, 1998
 * Ported to the kerneli patch by Marc Mutz <Marc@Mutz.com>
 * Ported to CryptoAPI by Colin Slater <hoho@tacomeat.net>
 *
 * The original author has disclaimed all copyright interest in this
 * code and thus put it in the public domain. The subsequent authors 
 * have put this under the GNU General Public License.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 * This code is a "clean room" implementation, written from the paper
 * _Twofish: A 128-Bit Block Cipher_ by Bruce Schneier, John Kelsey,
 * Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson, available
 * through http://www.counterpane.com/twofish.html
 *
 * For background information on multiplication in finite fields, used for
 * the matrix operations in the key schedule, see the book _Contemporary
 * Abstract Algebra_ by Joseph A. Gallian, especially chapter 22 in the
 * Third Edition.
 */
#ifndef _TWOFISH_
#define _TWOFISH_

#include "uint.h"

#define TF_MIN_KEY_SIZE 16
#define TF_MAX_KEY_SIZE 32
#define TF_BLOCK_SIZE 16

/* Structure for an expanded Twofish key.  s contains the key-dependent
 * S-boxes composed with the MDS matrix; w contains the eight "whitening"
 * subkeys, K[0] through K[7].	k holds the remaining, "round" subkeys.  Note
 * that k[i] corresponds to what the Twofish paper calls K[i+8]. */
struct twofish_ctx {
   u32 s[4][256], w[8], k[32];
};

/* Perform the key setup. return -1 if unsupported key length */
int twofish_setkey(void *cx, const u8 *key, u32 key_len, u32 *flags);


/* Encrypt one block.  in and out may be the same. */
void twofish_encrypt(void *cx, u8 *out, const u8 *in);


/* Decrypt one block.  in and out may be the same. */
void twofish_decrypt(void *cx, u8 *out, const u8 *in);

/* memcpy */
/*
void twofish_decrypt_fake(void *cx, u8 *out, const u8 *in);
void twofish_encrypt_fake(void *cx, u8 *out, const u8 *in);
*/

#endif