/*

 * 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.

 *

 */

 /**

  @file 

  @publishedPartner

  @released

 */

 #ifndef __BUFFEREDTRANSFORMATION_H__

 #define __BUFFEREDTRANSFORMATION_H__

 #include <e32std.h>

 #include <msymmetriccipher.h>

 #include <blocktransformation.h>

 class CPadding;

 /**

  * Abstract class, deriving from CSymmetricCipher, encapsulating the buffering

  * logic for block ciphers.

  *

  * It is responsible for feeding complete blocks of plaintext or ciphertext to

  * the underlying encryptor or decryptor.  Since the only difference between

  * block cipher encryption and decryption is the ProcessFinalL() call,

  * CBufferedTransformation implements all functions (by buffering and/or

  * forwarding to the encryptor/decryptor) except ProcessFinalL() and

  * MaxFinalOutputLength().

  *

  * See the Cryptography api-guide documentation for the rules that this class

  * and derived classes must follow.

  *

  */

 class CBufferedTransformation : public CSymmetricCipher

 {

 public:

 	/** The destructor frees all resources owned by the object, prior to its destruction. */

 	IMPORT_C virtual ~CBufferedTransformation();

 public:

 	/**

 	 * Encrypts or decrypts the input using the underlying block cipher, buffering

 	 * the input as necessary. 

 	 *

 	 * See the Cryptography api-guide documentation.

 	 *

 	 * @param aInput	The input is appended to the internal buffer (initially empty),

 	 *					then all whole blocks are encrypted using the underlying block

 	 *					transformation and written into aOutput. Any leftover bytes will

 	 *					be buffered.

 	 * @param aOutput	The resulting processed data appended to aOutput.  aOutput must

 	 *					have at least MaxOutputLength() empty bytes remaining in its length.

 	 */

 	virtual void Process(const TDesC8& aInput, TDes8& aOutput);

 	virtual TInt MaxOutputLength(TInt aInputLength) const;

 	virtual void Reset();

 	virtual TInt BlockSize() const;

 	virtual TInt KeySize() const;

 public:

 	/** 

 	 * Gets the underlying block transform.

 	 *

 	 * @return	A pointer to the CBlockTransformation object

 	 */

 	 IMPORT_C CBlockTransformation* BlockTransformer() const;

 protected:

 	/** @internalAll */

 	CBufferedTransformation();

 	/** @internalAll */

 	void ConstructL(CBlockTransformation* aBT, CPadding* aPadding);

 protected:

 	/** A block transformation object */

 	CBlockTransformation* iBT;

 	/** A descriptor which provides a buffer the length of the block size of iBT */

 	HBufC8* iInputStoreBuf;

 	/** A pointer to iInputStoreBuf */

 	TPtr8 iInputStore;

 	/** The padding */

 	CPadding* iPadding;

 };

 /**

  * Subclass of CBufferedTransformation for buffered encryption.

  *

  * Objects of this class are intialised with, and subsequently own, an encryptor

  * derived from CBlockTransformation and a subclass of CPadding.

  *

  */

 class CBufferedEncryptor : public CBufferedTransformation

 {

 public:

 	/**

 	 * Creates a CBufferedEncryptor object taking ownership of aBT and aPadding.

 	 *

 	 * @param aBT		Block transformation object (encryptor)

 	 * @param aPadding	Padding object (deriving from CPadding)

 	 * @return			A pointer to the new CBufferedEncryptor object

 	 */

 	IMPORT_C static CBufferedEncryptor* NewL(CBlockTransformation* aBT, 

 		CPadding* aPadding);

 	/**

 	 * Creates a CBufferedEncryptor object taking ownership of aBT and aPadding.

 	 *

 	 * The returned pointer is put onto the cleanup stack.

 	 *

 	 * @param aBT		Block transformation object (encryptor)

 	 * @param aPadding	Padding object (deriving from CPadding)

 	 * @return			A pointer to the new CBufferedEncryptor object

 	 */

 	IMPORT_C static CBufferedEncryptor* NewLC(CBlockTransformation* aBT, 

 		CPadding* aPadding);

 public:

 	/**

 	 * Completes an encryption operation using the underlying block transformation, but

 	 * first ensuring that input data is block aligned using the previously supplied

 	 * CPadding object.  

 	 *

 	 * See the Cryptography api-guide documentation.

 	 *

 	 * @param aInput	The final input data to be processed.

 	 * @param aOutput	The resulting processed data appended to aOutput.  aOutput must

 	 *					have at least MaxFinalOutputLength() empty bytes remaining in its

 	 *					length.

 	 */

 	virtual void ProcessFinalL(const TDesC8& aInput, TDes8& aOutput);

 	virtual TInt MaxFinalOutputLength(TInt aInputLength) const;

 protected:

 	/** @internalComponent */

 	void ConstructL(CBlockTransformation* aBT, CPadding* aPadding);

 	/** @internalAll */

 	CBufferedEncryptor();

 };

 /**

  * Subclass of CBufferedTransformation for buffered decryption.

  *

  * Objects of this class are intialised with, and subsequently own, a decryptor

  * derived from CBlockTransformation and a subclass of CPadding.

  *

  */

 class CBufferedDecryptor : public CBufferedTransformation

 {

 public:

 	/**

 	 * Creates a CBufferedDecryptor object taking ownership of aBT and aPadding.

 	 *

 	 * @param aBT		Block transformation object (decryptor)

 	 * @param aPadding	Padding object (deriving from CPadding)

 	 * @return			A pointer to the CBufferedDecryptor object.

 	 */

 	IMPORT_C static CBufferedDecryptor* NewL(CBlockTransformation* aBT, 

 		CPadding* aPadding);

 	/**

 	 * Creates a CBufferedDecryptor object taking ownership of aBT and aPadding.

 	 *

 	 * The returned pointer is put onto the cleanup stack.

 	 *

 	 * @param aBT		Block transformation object (decryptor)

 	 * @param aPadding	Padding object (deriving from CPadding)

 	 * @return			A pointer to the new CBufferedDecryptor object

 	 */

 	IMPORT_C static CBufferedDecryptor* NewLC(CBlockTransformation* aBT, 

 		CPadding* aPadding);

 public:

 	/**

 	 * Completes a decryption operation using the underlying block transformation and

 	 * unpads the decrypted data.

 	 *

 	 * @param aInput	The data to be processed and unpadded.  

 	 *					aInput must be a whole number of blocks.

 	 * @param aOutput	The resulting processed and unpadded data appened to aOutput.

 	 *					aOutput must have at least MaxFinalOutputLength() empty bytes

 	 *					remaining in its length.

 	 */

 	virtual void ProcessFinalL(const TDesC8& aInput, TDes8& aOutput);

 	virtual TInt MaxFinalOutputLength(TInt aInputLength) const;

 protected:

 	/** @internalComponent */

 	void ConstructL(CBlockTransformation* aBT, CPadding* aPadding);

 	/** @internalAll */

 	CBufferedDecryptor();

 };

 #endif	//	__CBUFFEREDTRANSFORMATION_H__