/*

 * Copyright (c) 2002-2009 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: 

 * ** IMPORTANT ** PublishedPartner API's in this file are published to 3rd party developers via the 

 * Symbian website. Changes to these API's should be treated as PublishedAll API changes and the Security TA should be consulted.

 * DES encryptor and decryptor implementation

 *

 */

 /**

  @file 

  @publishedPartner

  @released 

 */

 #ifndef __DATAENCRYPTIONSTANDARD_H__

 #define __DATAENCRYPTIONSTANDARD_H__

 #include "blocktransformation.h"

 #ifndef SYMBIAN_ENABLE_SPLIT_HEADERS

 #include <securityerr.h>

 #endif

 /** The size of the key schedule array (in 32-bit words).

 * 

 */

 const TUint KDESScheduleSizeInWords = 32;

 /**

 * Abstract base class for DES, implementing features common between DES encryption and

 * decryption. From CBlockTransformation

 * 

 */

 class CDES : public CBlockTransformation

 {

 public:	

 	virtual void Transform(TDes8& aBlock);

 	virtual TInt BlockSize() const;

 	virtual TInt KeySize() const;

 	virtual void Reset();

 	/**

 	 * Indicates whether a supplied key is weak. If the key is one of the weak keys

 	 * defined by the crypto library (e.g. {0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01})

 	 * ETrue is returned.

 	 * 

 	 * @param aKey	    		The Key to be checked. The key length must be

 	 							KDESKeySize = 8 bytes.

 	 * @return					Whether the key is weak (ETrue or EFalse)

 	 *						

 	 */

 	IMPORT_C static TBool IsWeakKey(const TDesC8& aKey);

 	virtual ~CDES();

 protected:

 	/** @internalAll */

 	CDES();

 	/** @internalAll */

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

 	virtual void SetKey(const TDesC8& aKey, TUint32* aKeyBuffer);

 	virtual void ConstructL(const TDesC8& aKey, TBool aCheckWeakKey);

 protected:

 	/** 

 	 * Key schedule array 

 	 *

 	 * Also used as the first key in triple-DES

 	 */

 	TUint32 iK1[KDESScheduleSizeInWords];	//	= 32

 	/** 

 	 * The initial key. 

 	 *

 	 * The key length must be KDESKeySize = 8 bytes.

 	 */

 	HBufC8* iKey;

 };

 /**

 * Concrete class for DES encryption.

 * 

 */

 class CDESEncryptor : public CDES

 {

 public:

 	/**

 	* Creates an instance of this class.

 	* 

 	* @param aKey			The key to be used for encryption. The key length must be

 	*						KDESKeySize = 8 bytes.

 	* @param aCheckWeakKey	Boolean determining whether to check the key against

 	*						a set of known weak key values. Defaults to ETrue. 

 	* @return				A pointer to the new CDESEncryptor object.

 	*

 	* @leave KErrWeakKey			If the key is a weak one, the function leaves having

 	*								previously cleaned up any previously allocated memory.

 	* @leave KErrKeyNotWeakEnough	If the key size is larger than that allowed by the

 	*								cipher strength restrictions of the crypto library.

 	* 								See TCrypto::IsSymmetricWeakEnoughL()

 	*/

 	IMPORT_C static CDESEncryptor* NewL(const TDesC8& aKey, TBool aCheckWeakKey = ETrue);

 	/**

 	* Creates an instance of this class and leaves it on the cleanup stack.

 	*

 	* @param aKey			The key to be used for encryption. The key length must be

 	*						KDESKeySize = 8 bytes.

 	* @param aCheckWeakKey	Boolean determining whether to check the resultant key against

 	*						a set of known weak key values. Defaults to ETrue. 

 	* @return				A pointer to the new CDESEncryptor object.

 	*

 	* @leave KErrWeakKey			If the key is a weak one, the function leaves having

 	*								previously cleaned up any previously allocated memory.

 	* @leave KErrKeyNotWeakEnough	If the key size is larger than that allowed by the

 	*								cipher strength restrictions of the crypto library.

 	*								See TCrypto::IsSymmetricWeakEnoughL()

 	*/

 	IMPORT_C static CDESEncryptor* NewLC(const TDesC8& aKey, TBool aCheckWeakKey = ETrue);

 private:

 	CDESEncryptor(void);

 };

 /**

 * Concrete class for DES decryption.

 *

 */

 class CDESDecryptor : public CDES

 {

 public:

 	/**

 	* Creates an instance of this class.

 	*

 	* @param aKey			The key to be used for decryption. The key length must be

 	*						KDESKeySize = 8 bytes.

 	* @param aCheckWeakKey	Boolean determining whether to check the resultant key against

 	*						a set of known weak key values. Defaults to ETrue.

 	* @return				A pointer to the new CDESDecryptor object.

 	*

 	* @leave KErrWeakKey			If the key is a weak one, the function leaves having

 	*								previously cleaned up any previously allocated memory.

 	* @leave KErrKeyNotWeakEnough	If the key size is larger than that allowed by the

 	*								cipher strength restrictions of the crypto library.

 	*								See TCrypto::IsSymmetricWeakEnoughL()

 	*/

 	IMPORT_C static CDESDecryptor* NewL(const TDesC8& aKey, TBool aCheckWeakKey = ETrue);

 	/**

 	* Creates an instance of this class and leaves it on the cleanup stack.

 	* 

 	* @param aKey			The key to be used for decryption. The key length must be

 	*						KDESKeySize = 8 bytes.

 	* @param aCheckWeakKey	Boolean determining whether to check the resultant key against

 	*						a set of known weak key values. Defaults to ETrue.

 	* @return				A pointer to the new CDESDecryptor object.

 	*

 	* @leave KErrWeakKey			If the key is a weak one, the function leaves having

 	*								previously cleaned up any previously allocated memory.

 	* @leave KErrKeyNotWeakEnough	If the key size is larger than that allowed by the

 	*								cipher strength restrictions of the crypto library.

 	*								See TCrypto::IsSymmetricWeakEnoughL()

 	*/

 	IMPORT_C static CDESDecryptor* NewLC(const TDesC8& aKey, TBool aCheckWeakKey = ETrue);

 protected:	//	From CDES

 	virtual void SetKey(const TDesC8& aKey, TUint32* aKeyBuffer);

 private:

 	CDESDecryptor(void);

 };

 #endif	//	__DATAENCRYPTIONSTANDARD_H__