fcrypt_b.c

des加解密算法程序包

/* crypto/des/fcrypt_b.c */
/* Copyright (C) 1995-1998 Eric Young ([e-mail])
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young ([e-mail]).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson ([e-mail]).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * 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 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young ([e-mail])"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson ([e-mail])"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 AUTHOR 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.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>

/* This version of crypt has been developed from my MIT compatible
 * DES library.
 * The library is available at pub/Crypto/DES at ftp.psy.uq.oz.au
 * Eric Young ([e-mail])
 */

#define DES_FCRYPT
#include "des_locl.h"
#undef DES_FCRYPT

#undef PERM_OP
#define PERM_OP(a,b,t,n,m) ((t)=((((a)>>(n))^(b))&(m)),\
	(b)^=(t),\
	(a)^=((t)<<(n)))

#undef HPERM_OP
#define HPERM_OP(a,t,n,m) ((t)=((((a)<<(16-(n)))^(a))&(m)),\
	(a)=(a)^(t)^(t>>(16-(n))))\

void fcrypt_body(DES_LONG *out, DES_key_schedule *ks, DES_LONG Eswap0,
		 DES_LONG Eswap1)
	{
	register DES_LONG l,r,t,u;
#ifdef DES_PTR
	register const unsigned char *des_SP=(const unsigned char *)DES_SPtrans;
#endif
	register DES_LONG *s;
	register int j;
	register DES_LONG E0,E1;

	l=0;
	r=0;

	s=(DES_LONG *)ks;
	E0=Eswap0;
	E1=Eswap1;

	for (j=0; j<25; j++)
		{
#ifndef DES_UNROLL
		register int i;

		for (i=0; i<32; i+=8)
			{
			D_ENCRYPT(l,r,i+0); /*  1 */
			D_ENCRYPT(r,l,i+2); /*  2 */
			D_ENCRYPT(l,r,i+4); /*  1 */
			D_ENCRYPT(r,l,i+6); /*  2 */
			}
#else
		D_ENCRYPT(l,r, 0); /*  1 */
		D_ENCRYPT(r,l, 2); /*  2 */
		D_ENCRYPT(l,r, 4); /*  3 */
		D_ENCRYPT(r,l, 6); /*  4 */
		D_ENCRYPT(l,r, 8); /*  5 */
		D_ENCRYPT(r,l,10); /*  6 */
		D_ENCRYPT(l,r,12); /*  7 */
		D_ENCRYPT(r,l,14); /*  8 */
		D_ENCRYPT(l,r,16); /*  9 */
		D_ENCRYPT(r,l,18); /*  10 */
		D_ENCRYPT(l,r,20); /*  11 */
		D_ENCRYPT(r,l,22); /*  12 */
		D_ENCRYPT(l,r,24); /*  13 */
		D_ENCRYPT(r,l,26); /*  14 */
		D_ENCRYPT(l,r,28); /*  15 */
		D_ENCRYPT(r,l,30); /*  16 */
#endif

		t=l;
		l=r;
		r=t;
		}
	l=ROTATE(l,3)&0xffffffffL;
	r=ROTATE(r,3)&0xffffffffL;

	PERM_OP(l,r,t, 1,0x55555555L);
	PERM_OP(r,l,t, 8,0x00ff00ffL);
	PERM_OP(l,r,t, 2,0x33333333L);
	PERM_OP(r,l,t,16,0x0000ffffL);
	PERM_OP(l,r,t, 4,0x0f0f0f0fL);

	out[0]=r;
	out[1]=l;
	}