crypto/libressl/crypto/idea/i_skey.c

   1 /* $OpenBSD: i_skey.c,v 1.3 2014/06/12 15:49:29 deraadt Exp $ */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include <openssl/crypto.h>
  60 #include <openssl/idea.h>
  61 #include "idea_lcl.h"
  62
  63 static IDEA_INT inverse(unsigned int xin);
  64 void idea_set_encrypt_key(const unsigned char *key, IDEA_KEY_SCHEDULE *ks)
  65         {
  66         int i;
  67         IDEA_INT *kt,*kf,r0,r1,r2;
  68
  69         kt= &(ks->data[0][0]);
  70         n2s(key,kt[0]); n2s(key,kt[1]); n2s(key,kt[2]); n2s(key,kt[3]);
  71         n2s(key,kt[4]); n2s(key,kt[5]); n2s(key,kt[6]); n2s(key,kt[7]);
  72
  73         kf=kt;
  74         kt+=8;
  75         for (i=0; i<6; i++)
  76                 {
  77                 r2= kf[1];
  78                 r1= kf[2];
  79                 *(kt++)= ((r2<<9) | (r1>>7))&0xffff;
  80                 r0= kf[3];
  81                 *(kt++)= ((r1<<9) | (r0>>7))&0xffff;
  82                 r1= kf[4];
  83                 *(kt++)= ((r0<<9) | (r1>>7))&0xffff;
  84                 r0= kf[5];
  85                 *(kt++)= ((r1<<9) | (r0>>7))&0xffff;
  86                 r1= kf[6];
  87                 *(kt++)= ((r0<<9) | (r1>>7))&0xffff;
  88                 r0= kf[7];
  89                 *(kt++)= ((r1<<9) | (r0>>7))&0xffff;
  90                 r1= kf[0];
  91                 if (i >= 5) break;
  92                 *(kt++)= ((r0<<9) | (r1>>7))&0xffff;
  93                 *(kt++)= ((r1<<9) | (r2>>7))&0xffff;
  94                 kf+=8;
  95                 }
  96         }
  97
  98 void idea_set_decrypt_key(IDEA_KEY_SCHEDULE *ek, IDEA_KEY_SCHEDULE *dk)
  99         {
 100         int r;
 101         IDEA_INT *fp,*tp,t;
 102
 103         tp= &(dk->data[0][0]);
 104         fp= &(ek->data[8][0]);
 105         for (r=0; r<9; r++)
 106                 {
 107                 *(tp++)=inverse(fp[0]);
 108                 *(tp++)=((int)(0x10000L-fp[2])&0xffff);
 109                 *(tp++)=((int)(0x10000L-fp[1])&0xffff);
 110                 *(tp++)=inverse(fp[3]);
 111                 if (r == 8) break;
 112                 fp-=6;
 113                 *(tp++)=fp[4];
 114                 *(tp++)=fp[5];
 115                 }
 116
 117         tp= &(dk->data[0][0]);
 118         t=tp[1];
 119         tp[1]=tp[2];
 120         tp[2]=t;
 121
 122         t=tp[49];
 123         tp[49]=tp[50];
 124         tp[50]=t;
 125         }
 126
 127 /* taken directly from the 'paper' I'll have a look at it later */
 128 static IDEA_INT inverse(unsigned int xin)
 129         {
 130         long n1,n2,q,r,b1,b2,t;
 131
 132         if (xin == 0)
 133                 b2=0;
 134         else
 135                 {
 136                 n1=0x10001;
 137                 n2=xin;
 138                 b2=1;
 139                 b1=0;
 140
 141                 do      {
 142                         r=(n1%n2);
 143                         q=(n1-r)/n2;
 144                         if (r == 0)
 145                                 { if (b2 < 0) b2=0x10001+b2; }
 146                         else
 147                                 {
 148                                 n1=n2;
 149                                 n2=r;
 150                                 t=b2;
 151                                 b2=b1-q*b2;
 152                                 b1=t;
 153                                 }
 154                         } while (r != 0);
 155                 }
 156         return((IDEA_INT)b2);
 157         }