/*

* Copyright (c) 2005 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "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:    Class for AES (in Counter Mode) encryption operations

*

*/

#ifndef __SRTPAESCTRCRYPTO_H__

#define __SRTPAESCTRCRYPTO_H__

#include <e32base.h>

class CSrtpAESCTRCrypto : public CBase

  	{

public:

    /**

    * Constructor.

    * @leave KErrNone if success, system-wide error code otherwise

    */

	IMPORT_C static CSrtpAESCTRCrypto* NewL();

	/**

    * AES CM cipher, produces generic keystream

    * @param aBitLength  key length.

    * @param aKey  Input key.

    * @param aIV  Integer Value (IV).

	* Returns HBufC8* generated keystream

	*/

	IMPORT_C HBufC8* KeystreamL(TUint aBitLength, const TDesC8& aKey, const TDesC8& aIV );

	/**

    * AES CM cipher, produces key stream and performs an XOR operation for the text

    * @param aKey  Input key.

    * @param aIV  Integer Value (IV).

    * @param aSrc source data which will be encrypted.

	* Returns HBufC8* decrypted/encrypted source

	*/

	IMPORT_C HBufC8* EncryptL(const TDesC8& aKey, const TDesC8& aIV, const TDesC8& aSrc);

	/**

    * Destructor

	*/

	~CSrtpAESCTRCrypto();

private:

    /**

    * Default constructor.

    */

	CSrtpAESCTRCrypto( );

	/**

    * Increases IV's value by one. 

    * Sets IV's last 32 bits to 0 if their value is max

    * @param aIV  Integer Value (IV).

	*/

	void IncreaseIV(TDes8& iv);

	#ifdef EUNIT_TESTING

        friend class UT_CSrtpAESCTRCrypto;

    #endif     

	};

#endif // __SrtpAESCTRCrypto_H__