set_key.c

IP网络语音通讯软件源代码. 不可多得的语音源代码

/* lib/des/set_key.c */
/* Copyright (C) 1995 Eric Young ([e-mail])
 * All rights reserved.
 * 
 * This file is part of an SSL implementation written
 * by Eric Young ([e-mail]).
 * The implementation was written so as to conform with Netscapes SSL
 * specification.  This library and applications are
 * FREE FOR COMMERCIAL AND NON-COMMERCIAL USE
 * as long as the following conditions are aheared to.
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.	If this code is used in a product,
 * Eric Young should be given attribution as the author of the parts 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 software developed by Eric Young ([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.]
 */

/* set_key.c v 1.4 eay 24/9/91
 * 1.4 Speed up by 400% :-)
 * 1.3 added register declarations.
 * 1.2 unrolled make_key_sched a bit more
 * 1.1 added norm_expand_bits
 * 1.0 First working version
 */
#include "des_locl.h"
#include "podd.h"
#include "sk.h"

#ifdef PROTO
static int check_parity(des_cblock *key);
#else
static int check_parity();
#endif

int des_check_key=0;

void des_set_odd_parity(key)
des_cblock FAR *key;
		{
		int i;

		for (i=0; i<DES_KEY_SZ; i++)
				(*key)[i]=odd_parity[(*key)[i]];
		}

#ifdef NEEDED
static int check_parity(key)
des_cblock (*key);
		{
		int i;

		for (i=0; i<DES_KEY_SZ; i++)
				{
				if ((*key)[i] != odd_parity[(*key)[i]])
						return(0);
				}
		return(1);
		}

/* Weak and semi week keys as take from
 * %A D.W. Davies
 * %A W.L. Price
 * %T Security for Computer Networks
 * %I John Wiley & Sons
 * %D 1984
 * Many thanks to [e-mail] (Steven Bellovin) for the reference
 * (and actual cblock values).
 */
#define NUM_WEAK_KEY	16
static des_cblock weak_keys[NUM_WEAK_KEY]={
		/* weak keys */
		{0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01},
		{0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE},
		{0x1F,0x1F,0x1F,0x1F,0x1F,0x1F,0x1F,0x1F},
		{0xE0,0xE0,0xE0,0xE0,0xE0,0xE0,0xE0,0xE0},
		/* semi-weak keys */
		{0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE},
		{0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01},
		{0x1F,0xE0,0x1F,0xE0,0x0E,0xF1,0x0E,0xF1},
		{0xE0,0x1F,0xE0,0x1F,0xF1,0x0E,0xF1,0x0E},
		{0x01,0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1},
		{0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1,0x01},
		{0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E,0xFE},
		{0xFE,0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E},
		{0x01,0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E},
		{0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E,0x01},
		{0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1,0xFE},
		{0xFE,0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1}};

int des_is_weak_key(key)
des_cblock (*key);
		{
		int i;

		for (i=0; i<NUM_WEAK_KEY; i++)
                /* Added == 0 to comparision, I obviously don't run
				 * this section very often :-(, thanks to
				 * [e-mail] for the fix
				 * eay 93/06/29 */
				if (memcmp(weak_keys[i],key,sizeof(key)) == 0) return(1);
		return(0);
		}
#endif		

/* NOW DEFINED IN des_local.h
 * See ecb_encrypt.c for a pseudo description of these macros. 
 * #define PERM_OP(a,b,t,n,m) ((t)=((((a)>>(n))^(b))&(m)),\
 *      (b)^=(t),\
 *		(a)=((a)^((t)<<(n))))
 */

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

static int shifts2[16]={0,0,1,1,1,1,1,1,0,1,1,1,1,1,1,0};

/* return 0 if key parity is odd (correct),
 * return -1 if key parity error,
 * return -2 if illegal weak key.
 */
int des_set_key(key, schedule)
des_cblock FAR *key;
des_key_schedule schedule;
		{
		register unsigned long c,d,t,s;
		register unsigned char FAR *in;
		register unsigned long *k;
		register int i;

#ifdef NEEDED
		if (des_check_key)
				{
				if (!check_parity(key))
						return(-1);

				if (des_is_weak_key(key))
						return(-2);
				}
#endif				

		k=(unsigned long *)schedule;
		in=(unsigned char FAR *)key;

		c2l(in,c);
		c2l(in,d);

		/* do PC1 in 60 simple operations */ 
/*		PERM_OP(d,c,t,4,0x0f0f0f0fL);
		HPERM_OP(c,t,-2, 0xcccc0000L);
		HPERM_OP(c,t,-1, 0xaaaa0000L);
		HPERM_OP(c,t, 8, 0x00ff0000L);
		HPERM_OP(c,t,-1, 0xaaaa0000L);
		HPERM_OP(d,t,-8, 0xff000000L);
		HPERM_OP(d,t, 8, 0x00ff0000L);
		HPERM_OP(d,t, 2, 0x33330000L);
		d=((d&0x00aa00aaL)<<7L)|((d&0x55005500L)>>7L)|(d&0xaa55aa55L);
		d=(d>>8)|((c&0xf0000000L)>>4);
		c&=0x0fffffffL; */

		/* I now do it in 47 simple operations :-)
		 * Thanks to John Fletcher ([e-mail])
		 * for the inspiration. :-) */
		PERM_OP (d,c,t,4,0x0f0f0f0fL);
		HPERM_OP(c,t,-2,0xcccc0000L);
		HPERM_OP(d,t,-2,0xcccc0000L);
		PERM_OP (d,c,t,1,0x55555555L);
		PERM_OP (c,d,t,8,0x00ff00ffL);
		PERM_OP (d,c,t,1,0x55555555L);
		d=		(((d&0x000000ffL)<<16L)| (d&0x0000ff00L)	 |
				 ((d&0x00ff0000L)>>16L)|((c&0xf0000000L)>>4L));
		c&=0x0fffffffL;

		for (i=0; i<ITERATIONS; i++)
				{
				if (shifts2[i])
						{ c=((c>>2L)|(c<<26L)); d=((d>>2L)|(d<<26L)); }
				else
						{ c=((c>>1L)|(c<<27L)); d=((d>>1L)|(d<<27L)); }
				c&=0x0fffffffL;
				d&=0x0fffffffL;
				/* could be a few less shifts but I am to lazy at this
				 * point in time to investigate */
				s=		des_skb[0][ (c	  )&0x3f				]|
						des_skb[1][((c>> 6)&0x03)|((c>> 7L)&0x3c)]|
						des_skb[2][((c>>13)&0x0f)|((c>>14L)&0x30)]|
						des_skb[3][((c>>20)&0x01)|((c>>21L)&0x06) |
												  ((c>>22L)&0x38)];
				t=		des_skb[4][ (d	  )&0x3f				]|
						des_skb[5][((d>> 7L)&0x03)|((d>> 8L)&0x3c)]|
						des_skb[6][ (d>>15L)&0x3f				 ]|
						des_skb[7][((d>>21L)&0x0f)|((d>>22L)&0x30)];

				/* table contained 0213 4657 */
				*(k++)=((t<<16L)|(s&0x0000ffffL))&0xffffffffL;
				s=	   ((s>>16L)|(t&0xffff0000L));
				
				s=(s<<4L)|(s>>28L);
				*(k++)=s&0xffffffffL;
				}
		return(0);
		}

#ifdef NEEDED
int des_key_sched(key, schedule)
des_cblock (FAR *key);
des_key_schedule schedule;
		{
		return(des_set_key(key,schedule));
		}
#endif