release/src/router/matrixssl/src/crypto/peersec/arc4.c

   1 /*
   2  *      arc4.c
   3  *      Release $Name: MATRIXSSL_1_8_8_OPEN $
   4  *
   5  *      ARC4 stream cipher implementation
   6  */
   7 /*
   8  *      Copyright (c) PeerSec Networks, 2002-2009. All Rights Reserved.
   9  *      The latest version of this code is available at http://www.matrixssl.org
  10  *
  11  *      This software is open source; you can redistribute it and/or modify
  12  *      it under the terms of the GNU General Public License as published by
  13  *      the Free Software Foundation; either version 2 of the License, or
  14  *      (at your option) any later version.
  15  *
  16  *      This General Public License does NOT permit incorporating this software
  17  *      into proprietary programs.  If you are unable to comply with the GPL, a
  18  *      commercial license for this software may be purchased from PeerSec Networks
  19  *      at http://www.peersec.com
  20  *
  21  *      This program is distributed in WITHOUT ANY WARRANTY; without even the
  22  *      implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  23  *      See the GNU General Public License for more details.
  24  *
  25  *      You should have received a copy of the GNU General Public License
  26  *      along with this program; if not, write to the Free Software
  27  *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  28  *      http://www.gnu.org/copyleft/gpl.html
  29  */
  30 /******************************************************************************/
  31
  32 #include "../cryptoLayer.h"
  33
  34 #ifdef USE_ARC4
  35
  36 /*
  37         Some accounts, such as O'Reilly's Secure Programming Cookbook say that no
  38         more than 2^30 bytes should be processed without rekeying, so we
  39         enforce that limit here.  FYI, this is equal to 1GB of data transferred.
  40 */
  41 #define ARC4_MAX_BYTES  0x40000000
  42
  43 /******************************************************************************/
  44 /*
  45         SSL_RSA_WITH_RC4_* cipher callbacks
  46  */
  47 void matrixArc4Init(sslCipherContext_t *ctx, unsigned char *key, int32 keylen)
  48 {
  49         unsigned char   index1, index2, tmp, *state;
  50         short                   counter;
  51
  52         ctx->arc4.byteCount = 0;
  53         state = &ctx->arc4.state[0];
  54
  55         for (counter = 0; counter < 256; counter++) {
  56                 state[counter] = (unsigned char)counter;
  57         }
  58         ctx->arc4.x = 0;
  59         ctx->arc4.y = 0;
  60         index1 = 0;
  61         index2 = 0;
  62
  63         for (counter = 0; counter < 256; counter++) {
  64                 index2 = (key[index1] + state[counter] + index2) & 0xff;
  65
  66                 tmp = state[counter];
  67                 state[counter] = state[index2];
  68                 state[index2] = tmp;
  69
  70                 index1 = (index1 + 1) % keylen;
  71         }
  72 }
  73
  74 int32 matrixArc4(sslCipherContext_t *ctx, unsigned char *in,
  75                            unsigned char *out, int32 len)
  76 {
  77         unsigned char   x, y, *state, xorIndex, tmp;
  78         short                   counter;
  79
  80         ctx->arc4.byteCount += len;
  81         if (ctx->arc4.byteCount > ARC4_MAX_BYTES) {
  82                 return -1;
  83         }
  84
  85         x = ctx->arc4.x;
  86         y = ctx->arc4.y;
  87         state = &ctx->arc4.state[0];
  88         for (counter = 0; counter < len; counter++) {
  89                 x = (x + 1) & 0xff;
  90                 y = (state[x] + y) & 0xff;
  91
  92                 tmp = state[x];
  93                 state[x] = state[y];
  94                 state[y] = tmp;
  95
  96                 xorIndex = (state[x] + state[y]) & 0xff;
  97
  98                 tmp = in[counter];
  99                 tmp ^= state[xorIndex];
 100                 out[counter] = tmp;
 101         }
 102         ctx->arc4.x = x;
 103         ctx->arc4.y = y;
 104         return len;
 105 }
 106
 107 #endif /* USE_ARC4 */
 108
 109 /******************************************************************************/