FreeBSD/Linux Kernel Cross Reference
sys/crypto/des/des_setkey.c

     /*      $FreeBSD$       */
     /*      $KAME: des_setkey.c,v 1.7 2001/09/10 04:03:58 itojun Exp $      */
     
     /* crypto/des/set_key.c */
     /* Copyright (C) 1995-1996 Eric Young (eay@mincom.oz.au)
      * All rights reserved.
      *
      * This file is part of an SSL implementation written
      * by Eric Young (eay@mincom.oz.au).
     * 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 (eay@mincom.oz.au)
     *
     * 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 <sys/param.h>
    #include <sys/systm.h>
    #include <crypto/des/des_locl.h>
    #include <crypto/des/podd.h>
    #include <crypto/des/sk.h>
    
    int des_check_key=0;
    
    void des_set_odd_parity(des_cblock *key)
    {
            int i;
    
            for (i=0; i<DES_KEY_SZ; i++)
                    (*key)[i]=odd_parity[(*key)[i]];
    }
    
    int des_check_key_parity(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 smb@ulysses.att.com (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,0x0E,0x0E,0x0E,0x0E},
           {0xE0,0xE0,0xE0,0xE0,0xF1,0xF1,0xF1,0xF1},
           /* 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(des_cblock *key)
   {
           int i;
   
           for (i=0; i<NUM_WEAK_KEY; i++)
                   /* Added == 0 to comparison, I obviously don't run
                    * this section very often :-(, thanks to
                    * engineering@MorningStar.Com for the fix
                    * eay 93/06/29
                    * Another problem, I was comparing only the first 4
                    * bytes, 97/03/18 */
                   if (memcmp(weak_keys[i],key,sizeof(des_cblock)) == 0) return(1);
           return(0);
   }
   
   /* 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))))
   
   int des_set_key(des_cblock *key, des_key_schedule schedule)
   {
           if (des_check_key)
           {
                   return des_set_key_checked(key, schedule);
           }
           else
           {
                   des_set_key_unchecked(key, schedule);
                   return 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_checked(des_cblock *key, des_key_schedule schedule)
   {
           if (!des_check_key_parity(key))
                   return(-1);
           if (des_is_weak_key(key))
                   return(-2);
           des_set_key_unchecked(key, schedule);
           return 0;
   }
   
   void des_set_key_unchecked(des_cblock *key, des_key_schedule schedule)
   {
           static int shifts2[16]={0,0,1,1,1,1,1,1,0,1,1,1,1,1,1,0};
           register DES_LONG c,d,t,s,t2;
           register const unsigned char *in;
           register DES_LONG *k;
           register int i;
   
           k = &schedule->ks.deslong[0];
           in = &(*key)[0];
   
           c2l(in,c);
           c2l(in,d);
   
           /* do PC1 in 47 simple operations :-)
            * Thanks to John Fletcher (john_fletcher@lccmail.ocf.llnl.gov)
            * 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>> 6L)&0x03)|((c>> 7L)&0x3c)]|
                           des_skb[2][((c>>13L)&0x0f)|((c>>14L)&0x30)]|
                           des_skb[3][((c>>20L)&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 */
                   t2=((t<<16L)|(s&0x0000ffffL))&0xffffffffL;
                   *(k++)=ROTATE(t2,30)&0xffffffffL;
   
                   t2=((s>>16L)|(t&0xffff0000L));
                   *(k++)=ROTATE(t2,26)&0xffffffffL;
           }
   }
   
   int des_key_sched(des_cblock *key, des_key_schedule schedule)
   {
           return(des_set_key(key,schedule));
   }
   
   void des_fixup_key_parity(des_cblock *key)
   {
           des_set_odd_parity(key);
   }

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