/*

* Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

#ifndef	__DESIMPL_H__

#define	__DESIMPL_H__

/**

@file 

@internalComponent

@released

*/

#include <e32base.h>

#include <e32cmn.h>

#include "keys.h"

#include "symmetriccipherimpl.h"

/**

Plug-in class for DES block cipher

*/

namespace SoftwareCrypto

	{

	using namespace CryptoSpi;

	NONSHARABLE_CLASS(CDesImpl) : public CSymmetricBlockCipherImpl

		{

	public:

		/**

		Creates an instance of a DES (Data Encryption Standard) symmetric cipher plug-in.

		@param aKey The key

		@param aCryptoMode whether to encrypt or decrypt

		@param aOperationMode The block cipher mode ECB, CBC, CTR etc

		@param aPadding The padding scheme to use None, SSLv3, PKCS#7

		@return A pointer to a CDesImpl instance

		*/

		static CDesImpl* NewL(TUid aImplementationUid, const CKey& aKey, 

			TUid aCryptoMode, TUid aOperationMode, TUid aPadding);

		/**

		Creates an instance of a DES (Data Encryption Standard) symmetric cipher plug-in.

		A pointer to the plug-in instance is placed on the cleanup stack.

		@param aKey The key

		@param aCryptoMode Whether to encrypt or decrypt

		@param aOperationMode T block cipher mode ECB, CBC, CTR etc

		@param aPadding The padding scheme to use None, SSLv3, PKCS#7

		@return A pointer to a CDesImpl instance

		*/

		static CDesImpl* NewLC(TUid aImplementationUid, const CKey& aKey, 

			TUid aCryptoMode,	TUid aOperationMode, TUid aPadding);

		// From CSymmetricCipherImpl

		TInt GetKeyStrength() const;

		TBool IsValidKeyLength(TInt aKeyBytes) const;

		TUid ImplementationUid() const;

		const CExtendedCharacteristics* GetExtendedCharacteristicsL();

		static CExtendedCharacteristics* CreateExtendedCharacteristicsL();

		/// Destructor

		~CDesImpl();		

	protected:

		/**

		Constructor

		@param aBlockBytes The block size in bytes (needed to allow

		3DES implementation to inherit from this class)

		@param aOperationMode The mode of operation e.g. CBC

		@param aCryptoMode Whether to encrypt or decrypt

		@param aPaddingMode The padding mode to use. None, SSL, PKCS#7

		*/

		CDesImpl(TUid aImplementationUid, TUint8 aBlockBytes, TUid aOperationMode, TUid aCryptoMode, TUid aPaddingMode);

		/**	

		Second phase of construction

		@param aKey The key object

		*/

		void ConstructL(const CKey& aKey);	

		// These protected functions are re-used by 3DES

		/**

		Transforms a block of data

		@param l The left half of the block to transform

		@param r The right half of the block to transform

		@param aKeySchedule The keyschedule to use for the transformation

		*/

		void DoTransform(TUint32& l, TUint32& r, const TUint32* aKeySchedule);

		/**

		Setup the key schedule for encryption

		@param aKey The input key

		@param aKeySchedule A pointer to the key schedule buffer

		*/

		void SetEncryptKeySchedule(const TDesC8& aKey, TUint32* aKeySchedule);

		/**

		Setup the key schedule for decryption

		@param aKey The input key

		@param aKeySchedule A pointer to the key schedule buffer		

		*/

		void SetDecryptKeySchedule(const TDesC8& aKey, TUint32* aKeySchedule);

		static const TUint8 KDesBlockBytes = 8;

		static const TUint8 KDesKeyBytes = 8;						

	private:														

		/**

		Creates the key schedule iK from CBlockTransformationImpl::iKey.

		This should be called from ConstructL and Reset

		*/

		void SetKeySchedule();			

		// From CSymmetricBlockCipherImpl

		void TransformEncrypt(TUint8* aBuffer, TUint aNumBlocks);

		void TransformDecrypt(TUint8* aBuffer, TUint aNumBlocks);

	private:

		TUid iImplementationUid; 

		/// Size of the key schedule in words

		static const TUint KKeyScheduleSize = 32;

		/// the key schedule

		TUint32 iK[KKeyScheduleSize];

		};

	}

#endif // __DESIMPL_H__