1 /*

     2 * Copyright (c) 2007 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:  AES encryption utility for drm engine use

    15 *

    16 */

    17 

    18 

    19 

    20 // INCLUDE FILES

    21 #include <e32std.h>

    22 

    23 #include <symmetric.h>

    24 #include <rijndael.h>

    25 

    26 #include <drmtypes.h>

    27 

    28 #include "drmaescrypto.h"

    29 

    30 // ============================ MEMBER FUNCTIONS ===============================

    31 // -----------------------------------------------------------------------------

    32 // DrmAesCrypto::DrmAesEncryptL

    33 // Encrypt data using a given key and insert initial vector on beginning

    34 // -----------------------------------------------------------------------------

    35 //

    36 EXPORT_C HBufC8* DrmAesCrypto::DrmAesEncryptL(

    37     const TDesC8& aKey,

    38     const TDesC8& aIV,

    39     const TBool aAddPadding,

    40     const TDesC8& aData )

    41     {

    42 

    43     HBufC8* retBuf( NULL );

    44 

    45     CModeCBCEncryptor* cbc( NULL );

    46     TInt lastBlockStart( 0 );

    47     TPtr8 data( NULL, 0, 0 );

    48 

    49     if( aIV.Length() != KDCFKeySize || aKey.Length() != KDCFKeySize )

    50         {

    51         User::Leave( KErrArgument );

    52         }

    53 

    54     cbc = CModeCBCEncryptor::NewL( CAESEncryptor::NewLC( aKey ), aIV );

    55     CleanupStack::Pop(); // CAESEncryptor, owned by cbc.

    56     CleanupStack::PushL( cbc );

    57 

    58     retBuf = HBufC8::NewLC( aData.Size() + aIV.Size() + KDCFKeySize );

    59     data.Set( retBuf->Des() );

    60     data.Copy( aIV );

    61     data.Append( aData );

    62 

    63     lastBlockStart = data.Length() - ( data.Length() % KDCFKeySize );

    64     // Loop through the data, excluding aIV

    65     for ( TInt i = KDCFKeySize; i  < lastBlockStart; i+= KDCFKeySize )

    66         {

    67         data.Set( retBuf->Des().MidTPtr( i, KDCFKeySize ) );

    68 

    69         cbc->Transform( data );

    70         }

    71 

    72     if ( aAddPadding )

    73         {

    74         TInt dataLength = retBuf->Length();

    75         TUint8 padding( static_cast< TUint8 >

    76             ( lastBlockStart + KDCFKeySize - dataLength ) );

    77 

    78         __ASSERT_DEBUG( lastBlockStart + KDCFKeySize - dataLength <= KDCFKeySize,

    79             User::Invariant() );

    80 

    81         retBuf->Des().SetLength( lastBlockStart + KDCFKeySize );

    82 

    83         for ( TInt i = dataLength; i < retBuf->Length(); ++i )

    84             {

    85             retBuf->Des()[ i ] = padding;

    86             }

    87 

    88         data.Set( retBuf->Des().MidTPtr( lastBlockStart, KDCFKeySize ) );

    89         cbc->Transform( data );

    90         }

    91 

    92     CleanupStack::Pop( retBuf );

    93     CleanupStack::PopAndDestroy( cbc );

    94     return retBuf;

    95 

    96     }

    97 

    98 //  End of File