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diff --git a/libktorrent/mse/rc4encryptor.h b/libktorrent/mse/rc4encryptor.h
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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