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/***************************************************************************
* Copyright (C) 2005 by Joris Guisson *
* joris.guisson@gmail.com *
* *
* 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 2 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, write to the *
* Free Software Foundation, Inc., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#ifndef MSERC4ENCRYPTOR_H
#define MSERC4ENCRYPTOR_H
#include <util/sha1hash.h>
#include <util/constants.h>
using bt::Uint8;
using bt::Uint32;
namespace mse
{
/**
* Helper class to do the actual encryption / decryption
*/
class RC4
{
Uint8 i,j;
Uint8 s[256];
public:
RC4(const Uint8* key,Uint32 size);
virtual ~RC4();
void process(const Uint8* in,Uint8* out,Uint32 size);
Uint8 process(Uint8 b);
};
/**
* @author Joris Guisson <joris.guisson@gmail.com>
*
* RC4 encryptor. Uses the RC4 algorithm to encrypt and decrypt data.
* This class has a static encryption buffer, which makes it not thread safe
* because the buffer is not protected by mutexes.
*/
class RC4Encryptor
{
RC4 enc,dec;
public:
RC4Encryptor(const bt::SHA1Hash & dkey,const bt::SHA1Hash & ekey);
virtual ~RC4Encryptor();
/**
* Decrypt some data, decryption happens in place (original data gets overwritten)
* @param data The data
* @param len Size of the data
*/
void decrypt(Uint8* data,Uint32 len);
/**
* Encrypt the data. Encryption happens into the static buffer.
* So that the data passed to this function is never overwritten.
* If we send pieces we point directly to the mmap region of data,
* this cannot be overwritten, hence the static buffer.
* @param data The data
* @param len The length of the data
* @return Pointer to the static buffer
*/
const Uint8* encrypt(const Uint8* data,Uint32 len);
/**
* Encrypt data, encryption will happen in the same buffer. So data will
* be changed replaced by it's encrypted version.
* @param data The data to encrypt
* @param len The length of the data
*/
void encryptReplace(Uint8* data,Uint32 len);
/**
* Encrypts one byte.
* @param b The byte to encrypt
* @return The encrypted byte
*/
Uint8 encrypt(Uint8 b) {return enc.process(b);}
};
}
#endif
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