desdata.h

DES算法原理及实现,实现了3DES和DES的程序过程

/*
*	 Header file for class of representing des data block
*    Copyright (C) 2007  Stone
*
*    This program is free software: you can redistribute it and/or modify
*    it under the terms of the GNU General Public License as published by
*    the Free Software Foundation, either version 3 of the License, or
*    (at your option) any later version.
*
*    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.  If not, see <http://www.gnu.org/licenses/>.
*
*    Contact me by [e-mail] 
*
*/
#ifndef DESDATA_H
#define DESDATA_H

#include "spbitset.h"

class deskey;

class desdata
{
	typedef spbitset<64> data_t;
public:
	desdata(void);
	~desdata(void);

	/*
	* encrypt the data by the key
	* return the encrypted data
	*/
	unsigned _int64 encrypt(const unsigned _int64& data,deskey& key);
	/*
	* decrypt the data by the key
	* return the decrypted data
	*/
	unsigned _int64 decrypt(const unsigned _int64& data,deskey& key);

private:
	/*
	* the core algorithm of encryption and decryption
	*/
	template <class iterator>
	unsigned _int64 des(const unsigned _int64& data,iterator begin,iterator end);

	/*
	* decompress 32 bits from 48 bits
	*/
	void sbox(data_t& right);

private:
	static size_t ipb[];
	static size_t ipr[];
	static size_t epd[];
	static size_t ppd[];
	static size_t sbx[8][4][16];

	//low 32 bits
	static data_t lo32;
};

#endif