/*

 * Copyright (c) 2006-2010 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 <cryptospi/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__