/*

* 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__