/*

* Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "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: 

*

*/

#include "dhimpl.h"

#include "pluginconfig.h"

using namespace SoftwareCrypto;

using namespace CryptoSpi;

/* CDHImpl */

CDHImpl::CDHImpl()

	{

	}

CDHImpl::~CDHImpl()

	{

	}

CDHImpl* CDHImpl::NewL(const CKey& aPrivateKey, const CCryptoParams* aParams)

	{

	CDHImpl* self = CDHImpl::NewLC(aPrivateKey, aParams);

	CleanupStack::Pop(self);

	return self;

	}

CDHImpl* CDHImpl::NewLC(const CKey& aPrivateKey, const CCryptoParams* aParams)

	{

	CDHImpl* self = new(ELeave) CDHImpl();

	CleanupStack::PushL(self);

	self->ConstructL(aPrivateKey, aParams);

	return self;

	}

CKey* CDHImpl::AgreeL(const CKey& aOtherPublicKey, const CCryptoParams* aParams)

	{

	/*

	 * unpack the parameters, we're expecting the N and G parameters

	 */

	const TInteger& N = aParams->GetBigIntL(KDhKeyParameterNUid);

	const TInteger& G = aParams->GetBigIntL(KDhKeyParameterGUid);

	const TInteger& privateN = iSharedParams->GetBigIntL(KDhKeyParameterNUid);

	const TInteger& privateG = iSharedParams->GetBigIntL(KDhKeyParameterGUid);

	const TInteger& X = aOtherPublicKey.GetBigIntL(KDhKeyParameterXUid);

	const TInteger& x = iPrivateKey->GetBigIntL(KDhKeyParameterxUid);

	/*

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

	 */

	if ((N != privateN) || (G != privateG))

		{

		User::Leave(KErrArgument);

		}

	/*

	 * do the key agreement algo X ^ x mod N

	 */

	RInteger result = TInteger::ModularExponentiateL(X, x, N);

	CleanupClosePushL(result);

	/*

	 * create the agreed key

	 */

	CCryptoParams* agreedKeyParameters = CCryptoParams::NewLC();

	agreedKeyParameters->AddL(result, KSymmetricKeyParameterUid);

	TKeyProperty agreedKeyProperties = {KDHAgreementUid, KCryptoPluginDhKeyAgreementUid,

									KDHAgreedKeyUid, KNonEmbeddedKeyUid };

	CKey* agreedKey = CKey::NewL(agreedKeyProperties, *agreedKeyParameters);

	// cleanup result, agreedKeyParameters

	CleanupStack::PopAndDestroy(2, &result);

	return agreedKey;

	}

TUid CDHImpl::ImplementationUid() const

	{

	return KCryptoPluginDhKeyAgreementUid;

	}

CExtendedCharacteristics* CDHImpl::CreateExtendedCharacteristicsL()

	{

	// All Symbian software plug-ins have unlimited concurrency, cannot be

	// reserved for exclusive use and are not CERTIFIED to be standards compliant.

	return CExtendedCharacteristics::NewL(KMaxTInt, EFalse);

	}

const CExtendedCharacteristics* CDHImpl::GetExtendedCharacteristicsL()

	{

	return CDHImpl::CreateExtendedCharacteristicsL();

	}