1 /*

     2 * Copyright (c) 2003-2009 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 the License "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: 

    15 *

    16 */

    17 

    18 

    19 #include <asymmetric.h>

    20 #include <asymmetrickeys.h>

    21 #include "keys.h"

    22 #include "keyconverter.h"

    23 #include "cryptokeyagreementapi.h"

    24 #include <cryptospi/cryptospidef.h>

    25 

    26 using namespace CryptoSpi;

    27 

    28 CKeyAgreement* GetKeyAgreementCryptoInterfaceLC(TUid aKeyAgreementAlgoUid,

    29 	  CKey& aPrivateKey, CCryptoParams* aParams)

    30 	{

    31 	CKeyAgreement* keyAgreementImpl =  0;

    32 	CKeyAgreementFactory::CreateKeyAgreementL(keyAgreementImpl,

    33 												aKeyAgreementAlgoUid, aPrivateKey,

    34 												aParams);

    35 	CleanupStack::PushL(keyAgreementImpl);

    36 	return keyAgreementImpl;

    37 	}

    38 

    39 EXPORT_C CDH* CDH::NewL(const CDHPrivateKey& aPrivateKey)

    40 	{

    41 	CDH* self = CDH::NewLC(aPrivateKey);

    42 	CleanupStack::Pop(self);

    43 	return self;

    44 	}

    45 

    46 EXPORT_C CDH* CDH::NewLC(const CDHPrivateKey& aPrivateKey)

    47 	{

    48 	CDH* self = new (ELeave) CDH(aPrivateKey);

    49 	CleanupStack::PushL(self);

    50 	return self;

    51 	}

    52 

    53 EXPORT_C HBufC8* CDH::AgreeL(const CDHPublicKey& aPublicKey) const

    54 	{

    55 	/*

    56 	 * both DH keys (ie our private and their public keys) must use the same N and G parameters

    57 	 */

    58 	if ((aPublicKey.N() != iPrivateKey.N()) || (aPublicKey.G() != iPrivateKey.G()))

    59 		{

    60 		User::Leave(KErrArgument);

    61 		}

    62 

    63 	CKey* privateKey = KeyConverter::CreateKeyL(iPrivateKey);

    64 	CleanupStack::PushL(privateKey);

    65 

    66 	/*

    67 	 *  package the common parameters N and G into a crypto params array

    68 	 * we've already checked that both the private and public keys have the 

    69 	 * same N and G so we only need build this array once for both creating 

    70 	 * and calling the interface

    71 	 */

    72 	CCryptoParams* keyParameters = CCryptoParams::NewLC();

    73 	keyParameters->AddL(aPublicKey.N(), KDhKeyParameterNUid);

    74 	keyParameters->AddL(aPublicKey.G(), KDhKeyParameterGUid);

    75 

    76 	/* 

    77 	 * get a DH key agreement interface

    78 	 */

    79 	CKeyAgreement* keyAgreementImpl =  GetKeyAgreementCryptoInterfaceLC(KDHAgreementUid, *privateKey, keyParameters);

    80 

    81 	/* 

    82 	 * call the api to get a DH agreed key

    83 	 */

    84 	CKey* publicKey = KeyConverter::CreateKeyL(aPublicKey);

    85 	CleanupStack::PushL(publicKey);

    86 

    87 	CKey* agreedKey = keyAgreementImpl->AgreeL(*publicKey, keyParameters);

    88 	CleanupStack::PushL(agreedKey);

    89 

    90 	/*

    91 	 * extract the agreed key

    92 	 */

    93 	const TInteger& agreedKeyData = agreedKey->GetBigIntL(KSymmetricKeyParameterUid);

    94 	HBufC8 *agreedKeyToReturn = agreedKeyData.BufferLC();

    95 	CleanupStack::Pop(agreedKeyToReturn);

    96 

    97 	/* 

    98 	 * cleanup stack - it should contain privateKey, keyAgreementImpl, publicKey, keyParameters and agreedKey

    99 	 */

   100 	CleanupStack::PopAndDestroy(5, privateKey);

   101 

   102 	return agreedKeyToReturn;

   103 	}

   104 

   105 EXPORT_C CDH::CDH(const CDHPrivateKey& aPrivateKey) : iPrivateKey(aPrivateKey)

   106 	{

   107 	}