191 lines
4.7 KiB
C
191 lines
4.7 KiB
C
/* set_key.c */
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/* Copyright (C) 1993 Eric Young - see README for more details */
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/* set_key.c v 1.4 eay 24/9/91
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* 1.4 Speed up by 400% :-)
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* 1.3 added register declarations.
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* 1.2 unrolled make_key_sched a bit more
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* 1.1 added norm_expand_bits
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* 1.0 First working version
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*/
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/*-
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* $Id: set_key.c,v 1.1.1.1 1994/09/30 14:49:51 csgr Exp $
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*/
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#include "des_locl.h"
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#include "podd.h"
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#include "sk.h"
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static int check_parity();
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int des_check_key=0;
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void des_set_odd_parity(key)
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des_cblock *key;
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{
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int i;
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for (i=0; i<DES_KEY_SZ; i++)
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(*key)[i]=odd_parity[(*key)[i]];
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}
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static int check_parity(key)
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des_cblock *key;
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{
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int i;
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for (i=0; i<DES_KEY_SZ; i++)
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{
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if ((*key)[i] != odd_parity[(*key)[i]])
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return(0);
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}
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return(1);
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}
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/* Weak and semi week keys as take from
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* %A D.W. Davies
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* %A W.L. Price
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* %T Security for Computer Networks
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* %I John Wiley & Sons
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* %D 1984
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* Many thanks to smb@ulysses.att.com (Steven Bellovin) for the reference
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* (and actual cblock values).
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*/
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#define NUM_WEAK_KEY 16
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static des_cblock weak_keys[NUM_WEAK_KEY]={
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/* weak keys */
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0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,
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0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,
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0x1F,0x1F,0x1F,0x1F,0x1F,0x1F,0x1F,0x1F,
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0xE0,0xE0,0xE0,0xE0,0xE0,0xE0,0xE0,0xE0,
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/* semi-weak keys */
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0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE,
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0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01,
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0x1F,0xE0,0x1F,0xE0,0x0E,0xF1,0x0E,0xF1,
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0xE0,0x1F,0xE0,0x1F,0xF1,0x0E,0xF1,0x0E,
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0x01,0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1,
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0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1,0x01,
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0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E,0xFE,
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0xFE,0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E,
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0x01,0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E,
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0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E,0x01,
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0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1,0xFE,
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0xFE,0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1};
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int des_is_weak_key(key)
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des_cblock *key;
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{
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int i;
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for (i=0; i<NUM_WEAK_KEY; i++)
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/* Added == 0 to comparision, I obviously don't run
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* this section very often :-(, thanks to
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* engineering@MorningStar.Com for the fix
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* eay 93/06/29 */
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if (memcmp(weak_keys[i],key,sizeof(key)) == 0) return(1);
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return(0);
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}
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/* NOW DEFINED IN des_local.h
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* See ecb_encrypt.c for a pseudo description of these macros.
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* #define PERM_OP(a,b,t,n,m) ((t)=((((a)>>(n))^(b))&(m)),\
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* (b)^=(t),\
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* (a)=((a)^((t)<<(n))))
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*/
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#define HPERM_OP(a,t,n,m) ((t)=((((a)<<(16-(n)))^(a))&(m)),\
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(a)=(a)^(t)^(t>>(16-(n))))
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static char shifts2[16]={0,0,1,1,1,1,1,1,0,1,1,1,1,1,1,0};
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/* return 0 if key parity is odd (correct),
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* return -1 if key parity error,
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* return -2 if illegal weak key.
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*/
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int des_set__key(key,schedule)
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des_cblock *key;
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des_key_schedule schedule;
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{
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register unsigned long c,d,t,s;
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register unsigned char *in;
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register unsigned long *k;
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register int i;
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if (des_check_key)
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{
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if (!check_parity(key))
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return(-1);
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if (des_is_weak_key(key))
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return(-2);
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}
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k=(unsigned long *)schedule;
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in=(unsigned char *)key;
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c2l(in,c);
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c2l(in,d);
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/* do PC1 in 60 simple operations */
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/* PERM_OP(d,c,t,4,0x0f0f0f0f);
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HPERM_OP(c,t,-2, 0xcccc0000);
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HPERM_OP(c,t,-1, 0xaaaa0000);
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HPERM_OP(c,t, 8, 0x00ff0000);
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HPERM_OP(c,t,-1, 0xaaaa0000);
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HPERM_OP(d,t,-8, 0xff000000);
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HPERM_OP(d,t, 8, 0x00ff0000);
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HPERM_OP(d,t, 2, 0x33330000);
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d=((d&0x00aa00aa)<<7)|((d&0x55005500)>>7)|(d&0xaa55aa55);
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d=(d>>8)|((c&0xf0000000)>>4);
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c&=0x0fffffff; */
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/* I now do it in 47 simple operations :-)
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* Thanks to John Fletcher (john_fletcher@lccmail.ocf.llnl.gov)
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* for the inspiration. :-) */
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PERM_OP (d,c,t,4,0x0f0f0f0f);
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HPERM_OP(c,t,-2,0xcccc0000);
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HPERM_OP(d,t,-2,0xcccc0000);
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PERM_OP (d,c,t,1,0x55555555);
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PERM_OP (c,d,t,8,0x00ff00ff);
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PERM_OP (d,c,t,1,0x55555555);
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d= (((d&0x000000ff)<<16)| (d&0x0000ff00) |
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((d&0x00ff0000)>>16)|((c&0xf0000000)>>4));
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c&=0x0fffffff;
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for (i=0; i<ITERATIONS; i++)
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{
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if (shifts2[i])
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{ c=((c>>2)|(c<<26)); d=((d>>2)|(d<<26)); }
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else
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{ c=((c>>1)|(c<<27)); d=((d>>1)|(d<<27)); }
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c&=0x0fffffff;
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d&=0x0fffffff;
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/* could be a few less shifts but I am to lazy at this
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* point in time to investigate */
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s= des_skb[0][ (c )&0x3f ]|
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des_skb[1][((c>> 6)&0x03)|((c>> 7)&0x3c)]|
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des_skb[2][((c>>13)&0x0f)|((c>>14)&0x30)]|
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des_skb[3][((c>>20)&0x01)|((c>>21)&0x06) |
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((c>>22)&0x38)];
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t= des_skb[4][ (d )&0x3f ]|
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des_skb[5][((d>> 7)&0x03)|((d>> 8)&0x3c)]|
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des_skb[6][ (d>>15)&0x3f ]|
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des_skb[7][((d>>21)&0x0f)|((d>>22)&0x30)];
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/* table contained 0213 4657 */
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*(k++)=((t<<16)|(s&0x0000ffff))&0xffffffff;
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s= ((s>>16)|(t&0xffff0000));
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s=(s<<4)|(s>>28);
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*(k++)=s&0xffffffff;
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}
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return(0);
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}
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int des_key_sched(key,schedule)
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des_cblock *key;
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des_key_schedule schedule;
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{
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return(des_set__key(key,schedule));
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}
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