sl@0: /*
sl@0: * Copyright (c) 2006-2010 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of the License "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description: 
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: #ifndef	ARC4IMPL_H
sl@0: #define	ARC4IMPL_H
sl@0: 
sl@0: /**
sl@0: @file 
sl@0: @internalComponent
sl@0: @released
sl@0: */
sl@0: 
sl@0: #include "symmetriccipherimpl.h"
sl@0: #include <e32base.h>
sl@0: #include <e32cmn.h>
sl@0: #include <cryptospi/keys.h>
sl@0: 
sl@0: 
sl@0: /**
sl@0: Plug-in class for ARC4 stream cipher
sl@0: */
sl@0: namespace SoftwareCrypto
sl@0: 	{
sl@0: 	using namespace CryptoSpi;
sl@0: 
sl@0: 	NONSHARABLE_CLASS(CArc4Impl) : public CSymmetricStreamCipherImpl
sl@0: 		{
sl@0: 	public:
sl@0: 		
sl@0: 		/** 
sl@0: 		Number of bytes to discard by default from an ARC4 key stream. 
sl@0: 		*/
sl@0: 		static const TUint KDefaultDiscardBytes = 768;
sl@0: 
sl@0: 		/** 
sl@0: 		The size of the substitution box (i.e. lookup table) in bytes. 
sl@0: 		*/
sl@0: 		static const TInt KSBoxSize = 256;
sl@0: 
sl@0: 		/** 
sl@0: 		Maximum ARC4 key size in bytes.2048 bits 
sl@0: 		*/
sl@0: 		static const TInt KMaxARC4KeyBytes = 256; 
sl@0: 
sl@0: 		/**
sl@0: 		Creates an instance of an ARC4 symmetric cipher plug-in.
sl@0: 		@param aKey The key
sl@0: 		@param aDiscardBytes The number of bytes to drop from 
sl@0: 							the beginning of the key stream.
sl@0: 		@return A pointer to a CArc4Impl instance
sl@0: 		*/
sl@0: 		static CArc4Impl* NewL(const CKey& aKey, TInt aDiscardBytes);
sl@0: 
sl@0: 		/**
sl@0: 		Creates an instance of an ARC4 symmetric cipher plug-in,
sl@0: 		and leave it on the cleanup stack
sl@0: 		@param aKey The key
sl@0: 		@param aDiscardBytes The number of bytes to drop from 
sl@0: 							the beginning of the key stream.
sl@0: 		@return A pointer to a CArc4Impl instance
sl@0: 		*/
sl@0: 		static CArc4Impl* NewLC(const CKey& aKey, TInt aDiscardBytes);
sl@0: 
sl@0: 		//Destructor
sl@0: 		~CArc4Impl();
sl@0: 
sl@0: 		//Override MPlugin virtual function
sl@0: 		void Reset();
sl@0: 		
sl@0: 		//Override CSymmetricCipherImpl virtual functions
sl@0: 		TUid ImplementationUid() const;
sl@0: 		TBool IsValidKeyLength(TInt aKeyBytes) const;
sl@0: 		
sl@0: 	private:
sl@0: 		//Constructor
sl@0: 		CArc4Impl(TInt aDiscardBytes);
sl@0: 			
sl@0: 		//second phase of construction	
sl@0: 		void ConstructL(const CKey& aKey);
sl@0: 				
sl@0: 		//Override CSymmetricStreamCipherImpl virtual functions
sl@0: 		void DoProcess(TDes8& aData);	
sl@0: 
sl@0: 		void GenerateSBox();
sl@0: 		TUint8 GenerateByte();
sl@0: 		void DiscardBytes(TInt aDiscardBytes);
sl@0: 
sl@0: 	private:
sl@0: 		TUint8 ix;
sl@0: 		TUint8 iy;
sl@0: 		TInt iDiscardBytes;
sl@0: 		TUint8 iState[KSBoxSize];
sl@0: 		};
sl@0: 	}
sl@0: 
sl@0: #endif //ARC4IMPL_H
sl@0: 
sl@0: 
sl@0: