crypto/rc4/rc4_enc.org

   1 /* crypto/rc4/rc4_enc.org */
   2 /* Copyright (C) 1995-1997 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 /* WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  60  *
  61  * Always modify rc4_enc.org since rc4_enc.c is automatically generated from
  62  * it during SSLeay configuration.
  63  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  64  */
  65
  66 #include "rc4.h"
  67
  68 /* if this is defined data[i] is used instead of *data, this is a %20
  69  * speedup on x86 */
  70 #define RC4_INDEX
  71
  72 char *RC4_version="RC4 part of SSLeay 0.8.1b 29-Jun-1998";
  73
  74 char *RC4_options()
  75         {
  76 #ifdef RC4_INDEX
  77         if (sizeof(RC4_INT) == 1)
  78                 return("rc4(idx,char)");
  79         else
  80                 return("rc4(idx,int)");
  81 #else
  82         if (sizeof(RC4_INT) == 1)
  83                 return("rc4(ptr,char)");
  84         else
  85                 return("rc4(ptr,int)");
  86 #endif
  87         }
  88
  89 /* RC4 as implemented from a posting from
  90  * Newsgroups: sci.crypt
  91  * From: sterndark@netcom.com (David Sterndark)
  92  * Subject: RC4 Algorithm revealed.
  93  * Message-ID: <sternCvKL4B.Hyy@netcom.com>
  94  * Date: Wed, 14 Sep 1994 06:35:31 GMT
  95  */
  96
  97 void RC4_set_key(key, len, data)
  98 RC4_KEY *key;
  99 int len;
 100 register unsigned char *data;
 101         {
 102         register RC4_INT tmp;
 103         register int id1,id2;
 104         register RC4_INT *d;
 105         unsigned int i;
 106
 107         d= &(key->data[0]);
 108         for (i=0; i<256; i++)
 109                 d[i]=i;
 110         key->x = 0;
 111         key->y = 0;
 112         id1=id2=0;
 113
 114 #define SK_LOOP(n) { \
 115                 tmp=d[(n)]; \
 116                 id2 = (data[id1] + tmp + id2) & 0xff; \
 117                 if (++id1 == len) id1=0; \
 118                 d[(n)]=d[id2]; \
 119                 d[id2]=tmp; }
 120
 121         for (i=0; i < 256; i+=4)
 122                 {
 123                 SK_LOOP(i+0);
 124                 SK_LOOP(i+1);
 125                 SK_LOOP(i+2);
 126                 SK_LOOP(i+3);
 127                 }
 128         }
 129
 130 void RC4(key, len, indata, outdata)
 131 RC4_KEY *key;
 132 unsigned long len;
 133 unsigned char *indata;
 134 unsigned char *outdata;
 135         {
 136         register RC4_INT *d;
 137         register RC4_INT x,y,tx,ty;
 138         int i;
 139
 140         x=key->x;
 141         y=key->y;
 142         d=key->data;
 143
 144 #define LOOP(in,out) \
 145                 x=((x+1)&0xff); \
 146                 tx=d[x]; \
 147                 y=(tx+y)&0xff; \
 148                 d[x]=ty=d[y]; \
 149                 d[y]=tx; \
 150                 (out) = d[(tx+ty)&0xff]^ (in);
 151
 152 #ifndef RC4_INDEX
 153 #define RC4_LOOP(a,b,i) LOOP(*((a)++),*((b)++))
 154 #else
 155 #define RC4_LOOP(a,b,i) LOOP(a[i],b[i])
 156 #endif
 157
 158         i= -(int)len;
 159         i=(int)(len>>3L);
 160         if (i)
 161                 {
 162                 for (;;)
 163                         {
 164                         RC4_LOOP(indata,outdata,0);
 165                         RC4_LOOP(indata,outdata,1);
 166                         RC4_LOOP(indata,outdata,2);
 167                         RC4_LOOP(indata,outdata,3);
 168                         RC4_LOOP(indata,outdata,4);
 169                         RC4_LOOP(indata,outdata,5);
 170                         RC4_LOOP(indata,outdata,6);
 171                         RC4_LOOP(indata,outdata,7);
 172 #ifdef RC4_INDEX
 173                         indata+=8;
 174                         outdata+=8;
 175 #endif
 176                         if (--i == 0) break;
 177                         }
 178                 }
 179         i=(int)len&0x07;
 180         if (i)
 181                 {
 182                 for (;;)
 183                         {
 184                         RC4_LOOP(indata,outdata,0); if (--i == 0) break;
 185                         RC4_LOOP(indata,outdata,1); if (--i == 0) break;
 186                         RC4_LOOP(indata,outdata,2); if (--i == 0) break;
 187                         RC4_LOOP(indata,outdata,3); if (--i == 0) break;
 188                         RC4_LOOP(indata,outdata,4); if (--i == 0) break;
 189                         RC4_LOOP(indata,outdata,5); if (--i == 0) break;
 190                         RC4_LOOP(indata,outdata,6); if (--i == 0) break;
 191                         }
 192                 }
 193         key->x=x;
 194         key->y=y;
 195         }