crypto/wvxor.cc

   1 /*
   2  * Worldvisions Tunnel Vision Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * XOR cryptography abstractions.
   6  * Could use this to implement short one time pads.
   7  */
   8 #include "wvxor.h"
   9
  10 /***** WvXOREncoder *****/
  11
  12 WvXOREncoder::WvXOREncoder(const void *_key, size_t _keylen) :
  13     keylen(_keylen), keyoff(0)
  14 {
  15     key = new unsigned char[keylen];
  16     memcpy(key, _key, keylen);
  17 }
  18
  19
  20 WvXOREncoder::~WvXOREncoder()
  21 {
  22     deletev key;
  23 }
  24
  25
  26 bool WvXOREncoder::_encode(WvBuf &inbuf, WvBuf &outbuf, bool flush)
  27 {
  28     size_t len;
  29     while ((len = inbuf.optgettable()) != 0)
  30     {
  31         const unsigned char *data = inbuf.get(len);
  32         unsigned char *out = outbuf.alloc(len);
  33
  34         // FIXME: this loop is SLOW! (believe it or not)
  35         while (len-- > 0)
  36         {
  37             *out++ = (*data++) ^ key[keyoff++];
  38             keyoff %= keylen;
  39         }
  40     }
  41     return true;
  42 }
  43
  44 /***** WvXORStream *****/
  45
  46 WvXORStream::WvXORStream(WvStream *_cloned,
  47     const void *_key, size_t _keysize) :
  48     WvEncoderStream(_cloned)
  49 {
  50     readchain.append(new WvXOREncoder(_key, _keysize), true);
  51     writechain.append(new WvXOREncoder(_key, _keysize), true);
  52 }