crypto/rc5/rc5_skey.c

   1 /* crypto/rc5/rc5_skey.c */
   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 "rc5.h"
  60 #include "rc5_locl.h"
  61
  62 void RC5_32_set_key(key,len,data,rounds)
  63 RC5_32_KEY *key;
  64 int len;
  65 unsigned char *data;
  66 int rounds;
  67         {
  68         RC5_32_INT L[64],l,ll,A,B,*S,k;
  69         int i,j,m,c,t,ii,jj;
  70
  71         if (    (rounds != RC5_16_ROUNDS) &&
  72                 (rounds != RC5_12_ROUNDS) &&
  73                 (rounds != RC5_8_ROUNDS))
  74                 rounds=RC5_16_ROUNDS;
  75
  76         key->rounds=rounds;
  77         S= &(key->data[0]);
  78         j=0;
  79         for (i=0; i<=(len-8); i+=8)
  80                 {
  81                 c2l(data,l);
  82                 L[j++]=l;
  83                 c2l(data,l);
  84                 L[j++]=l;
  85                 }
  86         ii=len-i;
  87         if (ii)
  88                 {
  89                 k=len&0x07;
  90                 c2ln(data,l,ll,k);
  91                 L[j+0]=l;
  92                 L[j+1]=ll;
  93                 }
  94
  95         c=(len+3)/4;
  96         t=(rounds+1)*2;
  97         S[0]=RC5_32_P;
  98         for (i=1; i<t; i++)
  99                 S[i]=(S[i-1]+RC5_32_Q)&RC5_32_MASK;
 100
 101         j=(t>c)?t:c;
 102         j*=3;
 103         ii=jj=0;
 104         A=B=0;
 105         for (i=0; i<j; i++)
 106                 {
 107                 k=(S[ii]+A+B)&RC5_32_MASK;
 108                 A=S[ii]=ROTATE_l32(k,3);
 109                 m=(int)(A+B);
 110                 k=(L[jj]+A+B)&RC5_32_MASK;
 111                 B=L[jj]=ROTATE_l32(k,m);
 112                 if (++ii >= t) ii=0;
 113                 if (++jj >= c) jj=0;
 114                 }
 115         }
 116