1 /*

     2 * Copyright (c) 2004 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:    Provides a class for AES CM 128 key derivation

    15 *

    16 */

    17 

    18 

    19 

    20 

    21 #include "srtpkeyderivation_aescm128.h"

    22 #include "srtpaesctrcrypto.h"

    23 #include "srtpdef.h"

    24 #include "srtputils.h"

    25 

    26 // ---------------------------------------------------------------------------

    27 // CSRTPEncryptionAESCM128::NewL

    28 // ---------------------------------------------------------------------------

    29 //

    30 CSRTPKeyDerivation_AESCM128* CSRTPKeyDerivation_AESCM128::NewL()

    31     {

    32     CSRTPKeyDerivation_AESCM128* self = CSRTPKeyDerivation_AESCM128::NewLC();

    33     CleanupStack::Pop(self);

    34     return self;    

    35     }

    36 

    37 // ---------------------------------------------------------------------------

    38 // CSRTPKeyDerivation_AESCM128::NewLC

    39 // ---------------------------------------------------------------------------

    40 //

    41 CSRTPKeyDerivation_AESCM128* CSRTPKeyDerivation_AESCM128::NewLC()

    42     {

    43     CSRTPKeyDerivation_AESCM128* self = new( ELeave ) CSRTPKeyDerivation_AESCM128();

    44     CleanupStack::PushL( self );

    45     self->ConstructL();

    46     return self;

    47     }

    48 

    49 

    50 // ---------------------------------------------------------------------------

    51 // CSRTPKeyDerivation_AESCM128::PRF_128BitL

    52 // ---------------------------------------------------------------------------

    53 //

    54 HBufC8* CSRTPKeyDerivation_AESCM128::PRF_128BitL(TUint aBitLength, 

    55                                               const TDesC8& aKey, 

    56                                               const TDesC8& aIV)

    57     {    

    58     HBufC8* paddedIV = NULL;

    59     HBufC8* keystream = NULL;

    60     TBuf8<1> padChar;

    61 

    62     // if the IV value is shorter than the AES block size (128 bits, 16 octets),

    63     // --> do the padding       

    64     if (aIV.Length() < KAESCM128BlockSizeInBytes)

    65         {

    66         paddedIV = HBufC8::NewMaxL(KAESCM128BlockSizeInBytes);

    67         CleanupStack::PushL(paddedIV);

    68         TUint8* ptr = const_cast<TUint8*>(paddedIV->Des().Ptr());

    69         

    70         Mem::FillZ( ptr, KAESCM128BlockSizeInBytes);        

    71         Mem::Copy( ptr, aIV.Ptr(), aIV.Length() );                    

    72         }

    73         

    74      if (!paddedIV)

    75         {

    76         // get the AES keystream with the original IV value       

    77         keystream = iEncryptor->KeystreamL(aBitLength, aKey, aIV);            

    78         }

    79      else

    80         {        

    81         // get the AES keystream with the padded IV value       

    82         keystream = iEncryptor->KeystreamL(aBitLength, aKey, *paddedIV);            

    83         }

    84 

    85     if (paddedIV)

    86         {

    87         CleanupStack::Pop(paddedIV);

    88         delete paddedIV; paddedIV=NULL;

    89         } 

    90         

    91     return keystream;

    92     }

    93 

    94 

    95 // ---------------------------------------------------------------------------

    96 // CSRTPKeyDerivation_AESCM128::ConstructL

    97 // ---------------------------------------------------------------------------

    98 //

    99 void CSRTPKeyDerivation_AESCM128::ConstructL()

   100     {    

   101     // Create AES-CTR Wrapper

   102     iEncryptor = CSrtpAESCTRCrypto::NewL();        

   103         

   104     }

   105 

   106 // ---------------------------------------------------------------------------

   107 // CSRTPKeyDerivation_AESCM128::~CSRTPKeyDerivation_AESCM128

   108 // ---------------------------------------------------------------------------

   109 //

   110 CSRTPKeyDerivation_AESCM128::~CSRTPKeyDerivation_AESCM128()

   111     {    

   112     // delete AES-CTR Wrapper

   113     delete iEncryptor;

   114         

   115     }

   116 

   117 // ---------------------------------------------------------------------------

   118 // CSRTPKeyDerivation_AESCM128::CSRTPKeyDerivation_AESCM128

   119 // ---------------------------------------------------------------------------

   120 //

   121 CSRTPKeyDerivation_AESCM128::CSRTPKeyDerivation_AESCM128()

   122     {    

   123         

   124     }