cypher.h

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/*
 *  anytun
 *
 *  The secure anycast tunneling protocol (satp) defines a protocol used
 *  for communication between any combination of unicast and anycast
 *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
 *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
 *  ethernet, ip, arp ...). satp directly includes cryptography and
 *  message authentication based on the methodes used by SRTP.  It is
 *  intended to deliver a generic, scaleable and secure solution for
 *  tunneling and relaying of packets of any protocol.
 *
 *
 *  Copyright (C) 2007 anytun.org <satp@wirdorange.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _CYPHER_H_
#define _CYPHER_H_



#include "datatypes.h"
#include "buffer.h"

extern "C" {
#include <gcrypt.h>
}


#include <string>

class Cypher
{
public:
  Cypher() {};
  virtual ~Cypher() {};
 
  void setKey(Buffer key) {};
  void setSalt(Buffer salt) {};
  void cypher(Buffer& buf, seq_nr_t seq_nr, sender_id_t sender_id);
  
protected:
  void exor(Buffer& buf, const Buffer& bit_stream);
  virtual Buffer getBitStream(u_int32_t length, seq_nr_t seq_nr, sender_id_t sender_id) = 0;
};

class NullCypher : public Cypher
{
protected:
  Buffer getBitStream(u_int32_t length, seq_nr_t seq_nr, sender_id_t sender_id);
};

class AesIcmCypher : public Cypher
{
public:
  AesIcmCypher();
  ~AesIcmCypher();
  void setKey(Buffer key);
  void setSalt(Buffer salt);

  static const std::string MIN_GCRYPT_VERSION;
  static const u_int32_t GCRYPT_SEC_MEM;

protected:
  Buffer getBitStream(u_int32_t length, seq_nr_t seq_nr, sender_id_t sender_id);
  gcry_cipher_hd_t cipher_;
  Buffer salt_;

private:
  static bool gcrypt_initialized_;
};

const std::string AesIcmCypher::MIN_GCRYPT_VERSION = "1.2.3";
bool AesIcmCypher::gcrypt_initialized_ = false;
const u_int32_t AesIcmCypher::GCRYPT_SEC_MEM = 16384; // 16k secure memory

#endif

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