os/security/cryptoplugins/cryptospiplugins/source/softwarecrypto/arc4impl.h
author sl@SLION-WIN7.fritz.box
Fri, 15 Jun 2012 03:10:57 +0200
changeset 0 bde4ae8d615e
permissions -rw-r--r--
First public contribution.
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/*
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* Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
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* All rights reserved.
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* This component and the accompanying materials are made available
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* under the terms of the License "Eclipse Public License v1.0"
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* which accompanies this distribution, and is available
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* at the URL "http://www.eclipse.org/legal/epl-v10.html".
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*
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* Initial Contributors:
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* Nokia Corporation - initial contribution.
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*
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* Contributors:
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*
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* Description: 
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*
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*/
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#ifndef	ARC4IMPL_H
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#define	ARC4IMPL_H
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/**
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@file 
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@internalComponent
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@released
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*/
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#include "symmetriccipherimpl.h"
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#include <e32base.h>
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#include <e32cmn.h>
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#include "keys.h"
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/**
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Plug-in class for ARC4 stream cipher
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*/
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namespace SoftwareCrypto
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	{
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	using namespace CryptoSpi;
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	NONSHARABLE_CLASS(CArc4Impl) : public CSymmetricStreamCipherImpl
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		{
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	public:
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		/** 
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		Number of bytes to discard by default from an ARC4 key stream. 
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		*/
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		static const TUint KDefaultDiscardBytes = 768;
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		/** 
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		The size of the substitution box (i.e. lookup table) in bytes. 
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		*/
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		static const TInt KSBoxSize = 256;
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		/** 
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		Maximum ARC4 key size in bytes.2048 bits 
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		*/
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		static const TInt KMaxARC4KeyBytes = 256; 
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		/**
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		Creates an instance of an ARC4 symmetric cipher plug-in.
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		@param aKey The key
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		@param aDiscardBytes The number of bytes to drop from 
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							the beginning of the key stream.
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		@return A pointer to a CArc4Impl instance
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		*/
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		static CArc4Impl* NewL(const CKey& aKey, TInt aDiscardBytes);
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		/**
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		Creates an instance of an ARC4 symmetric cipher plug-in,
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		and leave it on the cleanup stack
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		@param aKey The key
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		@param aDiscardBytes The number of bytes to drop from 
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							the beginning of the key stream.
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		@return A pointer to a CArc4Impl instance
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		*/
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		static CArc4Impl* NewLC(const CKey& aKey, TInt aDiscardBytes);
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		//Destructor
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		~CArc4Impl();
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		//Override MPlugin virtual function
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		void Reset();
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		//Override CSymmetricCipherImpl virtual functions
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		TUid ImplementationUid() const;
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		TBool IsValidKeyLength(TInt aKeyBytes) const;
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		const CExtendedCharacteristics* GetExtendedCharacteristicsL();
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		static CExtendedCharacteristics* CreateExtendedCharacteristicsL();
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	private:
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		//Constructor
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		CArc4Impl(TInt aDiscardBytes);
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		//second phase of construction	
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		void ConstructL(const CKey& aKey);
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		//Override CSymmetricStreamCipherImpl virtual functions
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		void DoProcess(TDes8& aData);	
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		void GenerateSBox();
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		TUint8 GenerateByte();
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		void DiscardBytes(TInt aDiscardBytes);
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	private:
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		TUint8 ix;
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		TUint8 iy;
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		TInt iDiscardBytes;
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		TUint8 iState[KSBoxSize];
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		};
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	}
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#endif //ARC4IMPL_H
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