sl@0: /*
sl@0: * Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of the License "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description: 
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: #include "rc2impl.h"
sl@0: #include "keys.h"
sl@0: 
sl@0: #include "rc2table.h"
sl@0: #include "common/inlines.h"
sl@0: #include "pluginconfig.h"
sl@0: #include "symmetriccipherimpl.h"
sl@0: #include <cryptostrength.h>
sl@0: 
sl@0: using namespace SoftwareCrypto;
sl@0: 
sl@0: CRc2Impl::CRc2Impl(
sl@0: 	TUid aCryptoMode,
sl@0: 	TUid aOperationMode,
sl@0: 	TUid aPadding) :
sl@0: 	CSymmetricBlockCipherImpl(KRc2BlockBytes, aCryptoMode, aOperationMode, aPadding)
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: CRc2Impl* CRc2Impl::NewL(
sl@0: 	const CKey& aKey,
sl@0: 	TUid aCryptoMode,
sl@0: 	TUid aOperationMode,
sl@0: 	TUid aPadding,
sl@0: 	TInt aEffectiveKeyLenBits)	
sl@0: 	{
sl@0: 	CRc2Impl* self = CRc2Impl::NewLC(aKey, aCryptoMode, aOperationMode, aPadding, aEffectiveKeyLenBits);
sl@0: 	CleanupStack::Pop(self);
sl@0: 	return self;
sl@0: 	}
sl@0: 	
sl@0: CRc2Impl* CRc2Impl::NewLC(
sl@0: 	const CKey& aKey,
sl@0: 	TUid aCryptoMode,
sl@0: 	TUid aOperationMode,
sl@0: 	TUid aPadding,
sl@0: 	TInt aEffectiveKeyLenBits)
sl@0: 	{
sl@0: 	CRc2Impl* self = new(ELeave) CRc2Impl(aCryptoMode, aOperationMode, aPadding);
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL(aKey, aEffectiveKeyLenBits);
sl@0: 	
sl@0: 	const TDesC8& keyContent = aKey.GetTDesC8L(KSymmetricKeyParameterUid);
sl@0: 	TCrypto::IsSymmetricWeakEnoughL(BytesToBits(keyContent.Size()) - keyContent.Size());
sl@0: 	return self;
sl@0: 	}
sl@0: 		
sl@0: CRc2Impl::~CRc2Impl()
sl@0: 	{
sl@0: 	Mem::FillZ(&iK, sizeof(iK));
sl@0: 	}
sl@0: 	
sl@0: void CRc2Impl::ConstructL(const CKey& aKey, TInt aEffectiveKeyLenBits)	
sl@0: 	{
sl@0: 	iEffectiveKeyLenBits = aEffectiveKeyLenBits;	
sl@0: 	CSymmetricBlockCipherImpl::ConstructL(aKey);
sl@0: 	SetKeySchedule();
sl@0: 	}
sl@0: 	
sl@0: CExtendedCharacteristics* CRc2Impl::CreateExtendedCharacteristicsL()
sl@0: 	{
sl@0: 	// All Symbian software plug-ins have unlimited concurrency, cannot be reserved
sl@0: 	// for exclusive use and are not CERTIFIED to be standards compliant.
sl@0: 	return CExtendedCharacteristics::NewL(KMaxTInt, EFalse);
sl@0: 	}
sl@0: 
sl@0: const CExtendedCharacteristics* CRc2Impl::GetExtendedCharacteristicsL()
sl@0: 	{
sl@0: 	return CRc2Impl::CreateExtendedCharacteristicsL();
sl@0: 	}
sl@0: 
sl@0: TUid CRc2Impl::ImplementationUid() const
sl@0: 	{
sl@0: 	return KCryptoPluginRc2Uid;
sl@0: 	}
sl@0: 
sl@0: TBool CRc2Impl::IsValidKeyLength(TInt aKeyBytes) const
sl@0: 	{
sl@0: 	return ((aKeyBytes > 0 && aKeyBytes <= KRc2MaxKeySizeBytes) ? ETrue : EFalse);
sl@0: 	}	
sl@0: 	
sl@0: TInt CRc2Impl::GetKeyStrength() const
sl@0: 	{
sl@0: 	return Min(iEffectiveKeyLenBits, BytesToBits(iKeyBytes));
sl@0: 	}
sl@0: 
sl@0: void CRc2Impl::SetKeySchedule()
sl@0: 	{				
sl@0: 	TUint keyLen = iKey->Length();
sl@0: 	
sl@0: 	TUint8 L[KRc2MaxKeySizeBytes];	
sl@0: 	Mem::Copy((TUint8*)&L[0], (TUint8*)&(*iKey)[0], keyLen);
sl@0: 
sl@0: 	TInt i = keyLen;
sl@0: 	for (; i < KRc2MaxKeySizeBytes; i++)
sl@0: 		{
sl@0: 		L[i] = RC2_TABLE::PITABLE[(L[i-1] + L[i-keyLen]) & 255];
sl@0: 		}
sl@0: 
sl@0: 	TUint T8 = (iEffectiveKeyLenBits+7) / 8;
sl@0: 	TUint8 TM = (TUint8)(255 >> ((8-(iEffectiveKeyLenBits%8))%8));
sl@0: 	L[128-T8] = RC2_TABLE::PITABLE[L[128-T8] & TM];
sl@0: 
sl@0: 	for (i=127-T8; i>=0; i--)
sl@0: 		L[i] = RC2_TABLE::PITABLE[L[i+1] ^ L[i+T8]];
sl@0: 
sl@0: 	for (i=0; i < KRc2ExpandedKeyLen; i++)
sl@0: 		iK[i] = (TUint16)(L[2*i] + (L[2*i+1] << 8));
sl@0: 	}
sl@0: 
sl@0: #pragma warning (disable : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data
sl@0: void CRc2Impl::TransformEncrypt(
sl@0: 	TUint8* aBuffer,
sl@0: 	TUint aNumBlocks)
sl@0: 	{
sl@0: 	for (TInt blockNum = 0; blockNum < aNumBlocks; ++blockNum)
sl@0: 		{		
sl@0: 		ModeEncryptStart(aBuffer);
sl@0: 		
sl@0: 		TUint16 R0, R1, R2, R3;
sl@0: 		GetBlockLittleEndian(aBuffer, R0, R1, R2, R3);
sl@0: 		
sl@0: 		TInt i = 0;
sl@0: 		for (; i < 16; i++)
sl@0: 			{
sl@0: 			R0 += (R1 & ~R3) + (R2 & R3) + iK[4*i+0];
sl@0: 			R0 = rotlFixed(R0, 1);
sl@0: 
sl@0: 			R1 += (R2 & ~R0) + (R3 & R0) + iK[4*i+1];
sl@0: 			R1 = rotlFixed(R1, 2);
sl@0: 
sl@0: 			R2 += (R3 & ~R1) + (R0 & R1) + iK[4*i+2];
sl@0: 			R2 = rotlFixed(R2, 3);
sl@0: 
sl@0: 			R3 += (R0 & ~R2) + (R1 & R2) + iK[4*i+3];
sl@0: 			R3 = rotlFixed(R3, 5);
sl@0: 
sl@0: 			if (i == 4 || i == 10)
sl@0: 				{
sl@0: 				R0 += iK[R3 & 63];
sl@0: 				R1 += iK[R0 & 63];
sl@0: 				R2 += iK[R1 & 63];
sl@0: 				R3 += iK[R2 & 63];
sl@0: 				}
sl@0: 			}
sl@0: 		PutBlockLittleEndian(aBuffer, R0, R1, R2, R3);	
sl@0: 		ModeEncryptEnd(aBuffer);
sl@0: 		aBuffer += KRc2BlockBytes;
sl@0: 		}
sl@0: 	}
sl@0: #pragma warning (default : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data
sl@0: 
sl@0: 
sl@0: #pragma warning (disable : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data
sl@0: void CRc2Impl::TransformDecrypt(
sl@0: 	TUint8* aBuffer,
sl@0: 	TUint aNumBlocks)
sl@0: 	{
sl@0: 	for (TInt blockNum = 0; blockNum < aNumBlocks; ++blockNum)
sl@0: 		{		
sl@0: 		ModeDecryptStart(aBuffer);
sl@0: 
sl@0: 		TUint16 R0, R1, R2, R3;
sl@0: 		GetBlockLittleEndian(aBuffer, R0, R1, R2, R3);
sl@0: 
sl@0: 		TInt i = 15;
sl@0: 		for (; i >= 0; i--)
sl@0: 			{
sl@0: 			if (i == 4 || i == 10)
sl@0: 				{
sl@0: 				R3 -= iK[R2 & 63];
sl@0: 				R2 -= iK[R1 & 63];
sl@0: 				R1 -= iK[R0 & 63];
sl@0: 				R0 -= iK[R3 & 63];
sl@0: 				}
sl@0: 
sl@0: 			R3 = rotrFixed(R3, 5);
sl@0: 			R3 -= (R0 & ~R2) + (R1 & R2) + iK[4*i+3];
sl@0: 
sl@0: 			R2 = rotrFixed(R2, 3);
sl@0: 			R2 -= (R3 & ~R1) + (R0 & R1) + iK[4*i+2];
sl@0: 
sl@0: 			R1 = rotrFixed(R1, 2);
sl@0: 			R1 -= (R2 & ~R0) + (R3 & R0) + iK[4*i+1];
sl@0: 
sl@0: 			R0 = rotrFixed(R0, 1);
sl@0: 			R0 -= (R1 & ~R3) + (R2 & R3) + iK[4*i+0];
sl@0: 			}
sl@0: 
sl@0: 		PutBlockLittleEndian(aBuffer, R0, R1, R2, R3);
sl@0: 		ModeDecryptEnd(aBuffer);
sl@0: 		aBuffer += KRc2BlockBytes;
sl@0: 		}
sl@0: 	}
sl@0: #pragma warning (default : 4244)	//	conversion from 'int' to 'unsigned short', possible loss of data