/*

* 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	__3DESIMPL_H__

#define	__3DESIMPL_H__

/**

@file 

@internalComponent

@released

*/

#include <e32base.h>

#include <e32cmn.h>

#include "keys.h"

#include "desimpl.h"

/**

Plug-in class for 3DES block cipher

*/

namespace SoftwareCrypto

	{

	using namespace CryptoSpi;

	NONSHARABLE_CLASS(C3DesImpl) : public CDesImpl

		{

	public:

		/**

		Creates an instance of a 3DES (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 C3DesImpl instance

		*/

		static C3DesImpl* NewL(const CKey& aKey, 

			TUid aCryptoMode, TUid aOperationMode, TUid aPadding);

		/**

		Creates an instance of a 3DES (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 The block cipher mode ECB, CBC, CTR etc

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

		@return A pointer to a C3DesImpl instance

		*/

		static C3DesImpl* NewLC(const CKey& aKey, 

			TUid aCryptoMode, TUid aOperationMode, TUid aPadding);

		// From CSymmetricCipherImpl

		TBool IsValidKeyLength(TInt aKeyBytes) const;

		TInt GetKeyStrength() const;

		TUid ImplementationUid() const;

		const CExtendedCharacteristics* GetExtendedCharacteristicsL();

		static CExtendedCharacteristics* CreateExtendedCharacteristicsL();

		/// 3Destructor

		~C3DesImpl();

	private:

		/**

		Constructor

		@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

		*/

		C3DesImpl(TUid aOperationMode, TUid aCryptoMode, TUid aPaddingMode);

		///	second phase of construction	

		void ConstructL(const CKey& aKey);						

		/**

		Creates the key schedules iK1, iK2, iK3 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:

		/// Size of the key schedule in words

		static const TUint KKeyScheduleSize = 32;

		/// the key schedules

		TUint32 iK1[KKeyScheduleSize];

		TUint32 iK2[KKeyScheduleSize];

		TUint32 iK3[KKeyScheduleSize];

		static const TUint8 K3DesBlockBytes = 8;

		static const TUint8 K3DesKeyBytes = 24;

		};

	}

#endif // __3DESIMPL_H__