/*

 * 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 "desimpl.h"

 #include "destables.h"

 #include "common/inlines.h"

 #include "des.inl"

 #include "pluginconfig.h"

 #include "symmetriccipherimpl.h"

 #include <cryptostrength.h>

 //	bit 0 is left-most in byte

 static const TInt bytebit[] = {0200,0100,040,020,010,04,02,01};

 using namespace SoftwareCrypto;

 /* CDesImpl */

 CDesImpl::CDesImpl(

 	TUint8 aBlockBytes,

 	TUid aCryptoMode,

 	TUid aOperationMode,

 	TUid aPadding) :

 	CSymmetricBlockCipherImpl(aBlockBytes, aCryptoMode, aOperationMode, aPadding)

 	{

 	}

 CDesImpl* CDesImpl::NewL(const CKey& aKey, TUid aCryptoMode, TUid aOperationMode, TUid aPadding)

 	{

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

 	CleanupStack::Pop(self);

 	return self;

 	}

 CDesImpl* CDesImpl::NewLC(const CKey& aKey, TUid aCryptoMode, TUid aOperationMode, TUid aPadding)

 	{

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

 	CleanupStack::PushL(self);

 	self->ConstructL(aKey);

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

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

 	return self;

 	}

 CDesImpl::~CDesImpl()

 	{

 	// make sure key information isn't visible to other processes if the

 	// page is reused.

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

 	}

 void CDesImpl::ConstructL(const CKey& aKey)

 	{

 	CSymmetricBlockCipherImpl::ConstructL(aKey);

 	SetKeySchedule();

 	}		

 CExtendedCharacteristics* CDesImpl::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* CDesImpl::GetExtendedCharacteristicsL()

 	{

 	return CDesImpl::CreateExtendedCharacteristicsL();

 	}

 TUid CDesImpl::ImplementationUid() const

 	{

 	return KCryptoPluginDesUid;

 	}

 TBool CDesImpl::IsValidKeyLength(TInt aKeyBytes) const

 	{

 	return (aKeyBytes == KDesKeyBytes);

 	}

 TInt CDesImpl::GetKeyStrength() const

 	{

 	// parity bits are excluded

 	return BytesToBits(KDesKeyBytes - 8);

 	}	

 void CDesImpl::TransformEncrypt(

 	TUint8* aBuffer,

 	TUint aNumBlocks)

 	{

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

 		{		

 		ModeEncryptStart(aBuffer);

 		TUint32 l, r;

 		// Split the block into 2 word-sized big endian portions

 		GetBlockBigEndian(aBuffer, l, r);

 		IPerm(l,r);

 		DoTransform(l, r, iK);		

 		FPerm(l,r);

 		// Put the portions back into the block as little endian

 		PutBlockBigEndian(aBuffer, r, l);

 		ModeEncryptEnd(aBuffer);

 		aBuffer += KDesBlockBytes;

 		}

 	}	

 void CDesImpl::TransformDecrypt(

 	TUint8* aBuffer,

 	TUint aNumBlocks)

 	{

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

 		{		

 		ModeDecryptStart(aBuffer);

 		TUint32 l, r;

 		// Split the block into 2 word-sized big endian portions

 		GetBlockBigEndian(aBuffer, l, r);

 		IPerm(l,r);

 		DoTransform(l, r, iK);		

 		FPerm(l,r);

 		// Put the portions back into the block as little endian

 		PutBlockBigEndian(aBuffer, r, l);

 		ModeDecryptEnd(aBuffer);

 		aBuffer += KDesBlockBytes;

 		}

 	}

 void CDesImpl::SetKeySchedule()

 	{

 	if (iCryptoMode.iUid == KCryptoModeEncrypt)

 		{

 		SetEncryptKeySchedule(*iKey, iK);

 		}

 	else 

 		{

 		ASSERT(iCryptoMode.iUid == KCryptoModeDecrypt);

 		SetDecryptKeySchedule(*iKey, iK);

 		}	

 	}		

 void CDesImpl::DoTransform(TUint32& l, TUint32& r, const TUint32* aKeySchedule)

 	{

 	TInt i = 0;

 	for (; i<8; i++)

 		{

 		TUint32 work = rotrFixed(r, 4U) ^ aKeySchedule[4*i+0];

 		l ^= DES_TABLE::sbox[6][(work) & 0x3f]

 		  ^  DES_TABLE::sbox[4][(work >> 8) & 0x3f]

 		  ^  DES_TABLE::sbox[2][(work >> 16) & 0x3f]

 		  ^  DES_TABLE::sbox[0][(work >> 24) & 0x3f];

 		work = r ^ aKeySchedule[4*i+1];

 		l ^= DES_TABLE::sbox[7][(work) & 0x3f]

 		  ^  DES_TABLE::sbox[5][(work >> 8) & 0x3f]

 		  ^  DES_TABLE::sbox[3][(work >> 16) & 0x3f]

 		  ^  DES_TABLE::sbox[1][(work >> 24) & 0x3f];

 		work = rotrFixed(l, 4U) ^ aKeySchedule[4*i+2];

 		r ^= DES_TABLE::sbox[6][(work) & 0x3f]

 		  ^  DES_TABLE::sbox[4][(work >> 8) & 0x3f]

 		  ^  DES_TABLE::sbox[2][(work >> 16) & 0x3f]

 		  ^  DES_TABLE::sbox[0][(work >> 24) & 0x3f];

 		work = l ^ aKeySchedule[4*i+3];

 		r ^= DES_TABLE::sbox[7][(work) & 0x3f]

 		  ^  DES_TABLE::sbox[5][(work >> 8) & 0x3f]

 		  ^  DES_TABLE::sbox[3][(work >> 16) & 0x3f]

 		  ^  DES_TABLE::sbox[1][(work >> 24) & 0x3f];

 		}

 	}	

 void CDesImpl::SetEncryptKeySchedule(const TDesC8& aKey, TUint32* aKeySchedule)

 	{

 	TInt i=0, j=0, l=0, m=0;

 //	Form a byte array from aKey, taking endianess into account (little->big)	

 	TUint8 key[8];								//	For big endian byte array	

 	Mem::Copy(&key, &aKey[0], 8);

 	TUint8 buffer[56+56+8];

 	TUint8* const pc1m = &buffer[0];			/* place to modify pc1 into */

 	TUint8* const pcr = pc1m + 56;				/* place to rotate pc1 into */

 	TUint8* const ks = pcr + 56;

 	for (j=0; j<56; j++) 

 		{/* convert pc1 to bits of key */

 		l = DES_TABLE::pc1[j]-1;				/* integer bit location  */

 		m = l & 07;								/* find bit              */

 		pc1m[j]=(key[l>>3] &					/* find which key byte l is in */

 			bytebit[m])							/* and which bit of that byte */

 			? (TUint8)1 : (TUint8)0;			/* and store 1-bit result */

 		}

 	for (i=0; i<16; i++) 

 		{/* key chunk for each iteration */

 		Mem::FillZ(ks,8);							/* Clear key schedule */

 		for (j=0; j<56; j++)

 		/*	rotate pc1 the right amount */

 			pcr[j] = pc1m[(l=j+DES_TABLE::totrot[i])<(j<28? 28 : 56) ? l: l-28];

 		/* rotate left and right halves independently */

 		for (j=0; j<48; j++)

 			{/* select bits individually */

 			/* check bit that goes to ks[j] */

 			if (pcr[DES_TABLE::pc2[j]-1])

 				{/* mask it in if it's there */

 				l= j % 6;

 				ks[j/6] |= bytebit[l] >> 2;

 				}

 			}

 		/* Now convert to odd/even interleaved form for use in F */

 		(*(aKeySchedule+(2*i))) = ((TUint32)ks[0] << 24)

 			| ((TUint32)ks[2] << 16)

 			| ((TUint32)ks[4] << 8)

 			| ((TUint32)ks[6]);

 		(*(aKeySchedule+(2*i+1))) = ((TUint32)ks[1] << 24)

 			| ((TUint32)ks[3] << 16)

 			| ((TUint32)ks[5] << 8)

 			| ((TUint32)ks[7]);

 		}		

 	}

 void CDesImpl::SetDecryptKeySchedule(const TDesC8& aKey, TUint32* aKeySchedule)

 	{

 	SetEncryptKeySchedule(aKey, aKeySchedule);

 	ReverseKeySchedule(aKeySchedule);

 	}