cypher.cpp

   1 /*
   2  *  anytun
   3  *
   4  *  The secure anycast tunneling protocol (satp) defines a protocol used
   5  *  for communication between any combination of unicast and anycast
   6  *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
   7  *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
   8  *  ethernet, ip, arp ...). satp directly includes cryptography and
   9  *  message authentication based on the methodes used by SRTP.  It is
  10  *  intended to deliver a generic, scaleable and secure solution for
  11  *  tunneling and relaying of packets of any protocol.
  12  *
  13  *
  14  *  Copyright (C) 2007 anytun.org <satp@wirdorange.org>
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License version 2
  18  *  as published by the Free Software Foundation.
  19  *
  20  *  This program is distributed in the hope that it will be useful,
  21  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  *  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 (see the file COPYING included with this
  27  *  distribution); if not, write to the Free Software Foundation, Inc.,
  28  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  29  */
  30
  31 #include <stdexcept>
  32
  33 #include "datatypes.h"
  34
  35 #include "cypher.h"
  36
  37 void Cypher::cypher(Buffer& buf)
  38 {
  39   Buffer stream = getBitStream(buf.getLength());
  40   exor(buf, stream);
  41 }
  42
  43 void Cypher::exor(Buffer& buf, const Buffer& bit_stream)
  44 {
  45   try
  46   {
  47     for(u_int32_t i; i<buf.getLength(); ++i)
  48       buf[i] ^= bit_stream[i];
  49   }
  50   catch(std::out_of_range& o) {}
  51 }
  52
  53 Buffer NullCypher::getBitStream(u_int32_t length)
  54 {
  55   Buffer buf(length);
  56   for(u_int32_t i; i<length; ++i)
  57     buf[i] = 0;
  58   return buf;
  59 }
  60