/*

* 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 "rsaimpl.h"

#include "rsafunction.h"

#include "pluginconfig.h"

#include <cryptopanic.h>

#include <cryptostrength.h>

#include <securityerr.h>

using namespace SoftwareCrypto;

/* CRSAImpl */

CRSAImpl::CRSAImpl(

	TUid aImplementationUid,

	TUid aCryptoMode,

	TUid aPadding) : 

	CAsymmetricCipherImpl(aCryptoMode, aPadding),

	iImplementationUid(aImplementationUid)

	{

	}

CRSAImpl* CRSAImpl::NewL(TUid aImplementationUid, const CKey& aKey, TUid aCryptoMode, TUid aPadding)

	{

	CRSAImpl* self = CRSAImpl::NewLC(aImplementationUid, aKey, aCryptoMode, aPadding);

	CleanupStack::Pop(self);

	return self;

	}

CRSAImpl* CRSAImpl::NewLC(TUid aImplementationUid, const CKey& aKey, TUid aCryptoMode, TUid aPadding)

	{

	CRSAImpl* self = new(ELeave) CRSAImpl(aImplementationUid, aCryptoMode, aPadding);

	CleanupStack::PushL(self);

	self->ConstructL(aKey);

	return self;

	}

CRSAImpl::~CRSAImpl()

	{

	}

TInt CRSAImpl::GetMaximumOutputLengthL() const

	{

	const TInteger& N = iKey->GetBigIntL(KRsaKeyParameterNUid);

	if (iCryptoMode.iUid == KCryptoModeDecrypt)

		return N.ByteCount() - iPadding->MinPaddingLength();

	else

		return N.ByteCount();

	}

TInt CRSAImpl::GetMaximumInputLengthL() const

	{

	const TInteger& N = iKey->GetBigIntL(KRsaKeyParameterNUid);

	if (iCryptoMode.iUid == KCryptoModeEncrypt)

		return N.ByteCount() - iPadding->MinPaddingLength();

	else

		return N.ByteCount();

	}

void CRSAImpl::ConstructL(const CKey& aKey)

	{

	const TInteger& N = aKey.GetBigIntL(KRsaKeyParameterNUid);

	TCrypto::IsAsymmetricWeakEnoughL(N.BitCount());

	CAsymmetricCipherImpl::ConstructL(aKey);

	if (! IsValidKeyLengthL(N.ByteCount()))

		{

		User::Leave(KErrKeySize);

		}

	}

CExtendedCharacteristics* CRSAImpl::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* CRSAImpl::GetExtendedCharacteristicsL()

	{

	return CRSAImpl::CreateExtendedCharacteristicsL();

	}

TUid CRSAImpl::ImplementationUid() const

	{

	return iImplementationUid;

	}

void CRSAImpl::EncryptL(const TDesC8& aInput, TDes8& aOutput) const

	{

	__ASSERT_DEBUG(aOutput.MaxLength() >= GetMaximumOutputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

	__ASSERT_DEBUG(aInput.Length() <= GetMaximumInputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicInputTooLarge));

	HBufC8* buf = HBufC8::NewLC(GetMaximumOutputLengthL());

	TPtr8 ptr = buf->Des();

	iPadding->PadL(aInput, ptr);

	RInteger input = RInteger::NewL(ptr);

	CleanupStack::PushL(input);

	RInteger output;

	RSAFunction::EncryptL(*iKey, input, output);

	CleanupStack::PushL(output);

	aOutput.Append(*(output.BufferLC()));

	CleanupStack::PopAndDestroy(4, buf); //BufferLC, output, input, buf

	}

void CRSAImpl::DecryptL(const TDesC8& aInput, TDes8& aOutput) const

	{

	__ASSERT_DEBUG(aOutput.MaxLength() >= GetMaximumOutputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));

	__ASSERT_DEBUG(aInput.Length() <= GetMaximumInputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicInputTooLarge));

	RInteger input = RInteger::NewL(aInput);

	CleanupStack::PushL(input);

	RInteger output;

	RSAFunction::DecryptL(*iKey, input, output);

	CleanupStack::PushL(output);

	TPtrC8 ptr = *(output.BufferLC());

	iPadding->UnPadL(ptr, aOutput);

	CleanupStack::PopAndDestroy(3, &input); //BufferLC(), output, input

	}

void CRSAImpl::ProcessL(const TDesC8& aInput, TDes8& aOutput)

	{

	if (iCryptoMode.iUid == KCryptoModeEncrypt)

		{

		EncryptL(aInput, aOutput);

		}

	else

		{

		DecryptL(aInput, aOutput);

		}

	}

TBool CRSAImpl::IsValidKeyLengthL(TInt aKeyBytes) const

	{

	if (aKeyBytes < 1)

		return EFalse;

	switch (iCryptoMode.iUid)

		{

		case KCryptoModeEncrypt:

			// Check if GetMaximumInputLengthL() makes sense,

			// if not the key length must be too small

			if (GetMaximumInputLengthL() <= 0)

				return EFalse;

			break;

		case KCryptoModeDecrypt:

			// Check if GetMaximumOutputLengthL() makes sense,

			// if not the key length must be too small

			if (GetMaximumOutputLengthL() <= 0)

				return EFalse;

			break;

		}

	return ETrue;

	}