/*

 * 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 "rc2impl.h"

 #include "keys.h"

 #include "rc2table.h"

 #include "common/inlines.h"

 #include "pluginconfig.h"

 #include "symmetriccipherimpl.h"

 #include <cryptostrength.h>

 using namespace SoftwareCrypto;

 CRc2Impl::CRc2Impl(

 	TUid aCryptoMode,

 	TUid aOperationMode,

 	TUid aPadding) :

 	CSymmetricBlockCipherImpl(KRc2BlockBytes, aCryptoMode, aOperationMode, aPadding)

 	{

 	}

 CRc2Impl* CRc2Impl::NewL(

 	const CKey& aKey,

 	TUid aCryptoMode,

 	TUid aOperationMode,

 	TUid aPadding,

 	TInt aEffectiveKeyLenBits)	

 	{

 	CRc2Impl* self = CRc2Impl::NewLC(aKey, aCryptoMode, aOperationMode, aPadding, aEffectiveKeyLenBits);

 	CleanupStack::Pop(self);

 	return self;

 	}

 CRc2Impl* CRc2Impl::NewLC(

 	const CKey& aKey,

 	TUid aCryptoMode,

 	TUid aOperationMode,

 	TUid aPadding,

 	TInt aEffectiveKeyLenBits)

 	{

 	CRc2Impl* self = new(ELeave) CRc2Impl(aCryptoMode, aOperationMode, aPadding);

 	CleanupStack::PushL(self);

 	self->ConstructL(aKey, aEffectiveKeyLenBits);

 	const TDesC8& keyContent = aKey.GetTDesC8L(KSymmetricKeyParameterUid);

 	TCrypto::IsSymmetricWeakEnoughL(BytesToBits(keyContent.Size()) - keyContent.Size());

 	return self;

 	}

 CRc2Impl::~CRc2Impl()

 	{

 	Mem::FillZ(&iK, sizeof(iK));

 	}

 void CRc2Impl::ConstructL(const CKey& aKey, TInt aEffectiveKeyLenBits)	

 	{

 	iEffectiveKeyLenBits = aEffectiveKeyLenBits;	

 	CSymmetricBlockCipherImpl::ConstructL(aKey);

 	SetKeySchedule();

 	}

 CExtendedCharacteristics* CRc2Impl::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* CRc2Impl::GetExtendedCharacteristicsL()

 	{

 	return CRc2Impl::CreateExtendedCharacteristicsL();

 	}

 TUid CRc2Impl::ImplementationUid() const

 	{

 	return KCryptoPluginRc2Uid;

 	}

 TBool CRc2Impl::IsValidKeyLength(TInt aKeyBytes) const

 	{

 	return ((aKeyBytes > 0 && aKeyBytes <= KRc2MaxKeySizeBytes) ? ETrue : EFalse);

 	}	

 TInt CRc2Impl::GetKeyStrength() const

 	{

 	return Min(iEffectiveKeyLenBits, BytesToBits(iKeyBytes));

 	}

 void CRc2Impl::SetKeySchedule()

 	{				

 	TUint keyLen = iKey->Length();

 	TUint8 L[KRc2MaxKeySizeBytes];	

 	Mem::Copy((TUint8*)&L[0], (TUint8*)&(*iKey)[0], keyLen);

 	TInt i = keyLen;

 	for (; i < KRc2MaxKeySizeBytes; i++)

 		{

 		L[i] = RC2_TABLE::PITABLE[(L[i-1] + L[i-keyLen]) & 255];

 		}

 	TUint T8 = (iEffectiveKeyLenBits+7) / 8;

 	TUint8 TM = (TUint8)(255 >> ((8-(iEffectiveKeyLenBits%8))%8));

 	L[128-T8] = RC2_TABLE::PITABLE[L[128-T8] & TM];

 	for (i=127-T8; i>=0; i--)

 		L[i] = RC2_TABLE::PITABLE[L[i+1] ^ L[i+T8]];

 	for (i=0; i < KRc2ExpandedKeyLen; i++)

 		iK[i] = (TUint16)(L[2*i] + (L[2*i+1] << 8));

 	}

 #pragma warning (disable : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data

 void CRc2Impl::TransformEncrypt(

 	TUint8* aBuffer,

 	TUint aNumBlocks)

 	{

 	for (TInt blockNum = 0; blockNum < aNumBlocks; ++blockNum)

 		{		

 		ModeEncryptStart(aBuffer);

 		TUint16 R0, R1, R2, R3;

 		GetBlockLittleEndian(aBuffer, R0, R1, R2, R3);

 		TInt i = 0;

 		for (; i < 16; i++)

 			{

 			R0 += (R1 & ~R3) + (R2 & R3) + iK[4*i+0];

 			R0 = rotlFixed(R0, 1);

 			R1 += (R2 & ~R0) + (R3 & R0) + iK[4*i+1];

 			R1 = rotlFixed(R1, 2);

 			R2 += (R3 & ~R1) + (R0 & R1) + iK[4*i+2];

 			R2 = rotlFixed(R2, 3);

 			R3 += (R0 & ~R2) + (R1 & R2) + iK[4*i+3];

 			R3 = rotlFixed(R3, 5);

 			if (i == 4 || i == 10)

 				{

 				R0 += iK[R3 & 63];

 				R1 += iK[R0 & 63];

 				R2 += iK[R1 & 63];

 				R3 += iK[R2 & 63];

 				}

 			}

 		PutBlockLittleEndian(aBuffer, R0, R1, R2, R3);	

 		ModeEncryptEnd(aBuffer);

 		aBuffer += KRc2BlockBytes;

 		}

 	}

 #pragma warning (default : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data

 #pragma warning (disable : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data

 void CRc2Impl::TransformDecrypt(

 	TUint8* aBuffer,

 	TUint aNumBlocks)

 	{

 	for (TInt blockNum = 0; blockNum < aNumBlocks; ++blockNum)

 		{		

 		ModeDecryptStart(aBuffer);

 		TUint16 R0, R1, R2, R3;

 		GetBlockLittleEndian(aBuffer, R0, R1, R2, R3);

 		TInt i = 15;

 		for (; i >= 0; i--)

 			{

 			if (i == 4 || i == 10)

 				{

 				R3 -= iK[R2 & 63];

 				R2 -= iK[R1 & 63];

 				R1 -= iK[R0 & 63];

 				R0 -= iK[R3 & 63];

 				}

 			R3 = rotrFixed(R3, 5);

 			R3 -= (R0 & ~R2) + (R1 & R2) + iK[4*i+3];

 			R2 = rotrFixed(R2, 3);

 			R2 -= (R3 & ~R1) + (R0 & R1) + iK[4*i+2];

 			R1 = rotrFixed(R1, 2);

 			R1 -= (R2 & ~R0) + (R3 & R0) + iK[4*i+1];

 			R0 = rotrFixed(R0, 1);

 			R0 -= (R1 & ~R3) + (R2 & R3) + iK[4*i+0];

 			}

 		PutBlockLittleEndian(aBuffer, R0, R1, R2, R3);

 		ModeDecryptEnd(aBuffer);

 		aBuffer += KRc2BlockBytes;

 		}

 	}

 #pragma warning (default : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data