/*

* Copyright (c) 2005-2009 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 "pkcs12macdata.h"

using namespace PKCS12;

CDecPkcs12MacData::CDecPkcs12MacData()

	{

	}

EXPORT_C CDecPkcs12MacData* CDecPkcs12MacData::NewL(const TDesC8& aMacData, const TDesC8& aAuthSafeData)

	{

	CDecPkcs12MacData* self = new(ELeave) CDecPkcs12MacData();

	CleanupStack::PushL(self);

	self->ConstructL(aMacData, aAuthSafeData);

	CleanupStack::Pop(self);

	return self;

	}

CDecPkcs12MacData::~CDecPkcs12MacData()

	{

	delete iDigestInfo;

	}

void CDecPkcs12MacData::ConstructL(const TDesC8& aMacData, const TDesC8& aAuthSafeData)

	{

	iAuthSafeDataPtr.Set(aAuthSafeData);

	// MacData is a Sequence

	TASN1DecGeneric seqGen(aMacData);

	seqGen.InitL();

	if (seqGen.Tag() != EASN1Sequence || seqGen.Class() != EUniversal)

		{

		User::Leave(KErrArgument);

		}

	// Decode the MacData Sequence

	TASN1DecSequence seq;

	CArrayPtr<TASN1DecGeneric>* macDataSequence = seq.DecodeDERLC(seqGen);

	TInt macDataCount = macDataSequence->Count();

	// Check if Mac, MacSalt and Iteration Count are present

	// Iteration Count is 1 by default

	if (macDataCount < 2 || macDataCount > 3)

		{

		User::Leave(KErrArgument);

		}

	// DigestInfo

	const TASN1DecGeneric* macDataSequenceAt0 = macDataSequence->At(0);

	// DigestInfo is a Sequence

	if (macDataSequenceAt0->Tag() != EASN1Sequence || macDataSequenceAt0->Class() != EUniversal)

		{

		User::Leave(KErrArgument);

		}

	iDigestInfo = CPKCS7DigestInfo::NewL(macDataSequenceAt0->Encoding());

	// MacSalt

	const TASN1DecGeneric* macDataSequenceAt1 = macDataSequence->At(1);

	// MacSalt is an OctetString

	if (macDataSequenceAt1->Tag() != EASN1OctetString || macDataSequenceAt1->Class() != EUniversal)

		{

		User::Leave(KErrArgument);

		}  

    iMacSalt.Set(macDataSequenceAt1->GetContentDER());

    // Iteration Count

	if(macDataSequence->Count() == 3)

		{

		// Check for IterationCount

		const TASN1DecGeneric* macDataSequenceAt2 = macDataSequence->At(2);

		if (macDataSequenceAt2->Tag() != EASN1Integer || macDataSequenceAt2->Class() != EUniversal)

			{

			User::Leave(KErrArgument);

			}

		TASN1DecInteger intDecoder;

		iIterationCount = intDecoder.DecodeDERShortL(*macDataSequenceAt2);

		if(iIterationCount <= 0)

			{

			User::Leave(KErrArgument);

			}

		}

    // Assign the Default value as 1 if Iteration Count is not present.

	else

		{

		iIterationCount = KDefaultIterationCount;

		}	

	CleanupStack::PopAndDestroy(macDataSequence);

    }

EXPORT_C const CPKCS7DigestInfo& CDecPkcs12MacData::DigestInfo() const

	{

	return *iDigestInfo;

	}

EXPORT_C const TDesC8& CDecPkcs12MacData::MacSalt() const

	{

	return iMacSalt;	

	}

EXPORT_C TInt CDecPkcs12MacData::IterationCount() const

	{

	return iIterationCount;	

	}

EXPORT_C TBool CDecPkcs12MacData::VerifyIntegrityL(const TDesC& aPassword) const

	{	

	__UHEAP_MARK;

	HBufC8* encryptKey = HBufC8::NewMaxLC(KSha1HmacKeyLength);

	TPtr8 encryptedKey(encryptKey->Des());

	// Convert the supplied string to a byte string. Each character is converted to a big 

	// endian two-byte value, and a terminating NULL character is appended to the end.

	HBufC8* password = PKCS12KDF::GeneratePasswordLC(aPassword);

	PKCS12KDF::DeriveKeyL(encryptedKey, PKCS12KDF::EIDByteMACKey, *password ,MacSalt(), IterationCount());

	CMessageDigest* digest1 = NULL;

	TAlgorithmId algorithmId = DigestInfo().Algorithm();

	if (algorithmId != ESHA1)

		{

		User::Leave(KErrNotSupported);

		}

	digest1 = CSHA1::NewL();

	CleanupStack::PushL( digest1 );

	CHMAC* hmac1 = CHMAC::NewL( encryptedKey, digest1);

	CleanupStack::PushL( hmac1 );

	TPtrC8 tmpHash = hmac1->Final(iAuthSafeDataPtr);

	TInt ret = tmpHash.Compare(DigestInfo().Digest());

	TBool result;

	if(ret)

		{

		result = EFalse;

		}

	else

		{

		result = ETrue;

		}

	CleanupStack::PopAndDestroy(hmac1);

	CleanupStack::Pop(digest1);

	CleanupStack::PopAndDestroy(2,encryptKey); // encryptKey, password

	__UHEAP_MARKEND;

	return result;	

	}