--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rtp/srtpstack/inc/msrtpkeyderivation.h	Tue Feb 02 01:03:15 2010 +0200
@@ -0,0 +1,46 @@
+/*
+* Copyright (c) 2004 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:    Provides an abstract class for key derivation operations
+*
+*/
+
+
+
+
+#ifndef __MSRTP_KEYDERIVATION_H__
+#define __MSRTP_KEYDERIVATION_H__
+
+#include <e32base.h>
+
+class MSRTPKeyDerivation
+    {
+    public:
+        /**
+        * This function is called by SRTP for key derivation operation (PRF_n)
+        * regardless of the algorithm, the default is AESCM-128
+        * Produces key stream based on input key and IV value.
+        * PRF_n function is used to derive session key from desired master key.
+        * @param aBitLength Encryption key length
+        * @param aKey  Input key.
+        * @param aIV  Integer Value (IV).
+	    * Returns HBufC8* keystream 
+        */        
+        virtual HBufC8* PRF_128BitL(TUint aBitLength,
+                                const TDesC8& aKey, 
+                                const TDesC8& aIV) = 0;
+                                
+        virtual ~MSRTPKeyDerivation() { };                                
+    };
+
+#endif // __MSRTP_KEYDERIVATION_H__