os/security/cryptoplugins/cryptospiplugins/source/softwarecrypto/rsaimpl.cpp
author sl@SLION-WIN7.fritz.box
Fri, 15 Jun 2012 03:10:57 +0200
changeset 0 bde4ae8d615e
permissions -rw-r--r--
First public contribution.
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/*
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* Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
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* All rights reserved.
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* This component and the accompanying materials are made available
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* under the terms of the License "Eclipse Public License v1.0"
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* which accompanies this distribution, and is available
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* at the URL "http://www.eclipse.org/legal/epl-v10.html".
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*
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* Initial Contributors:
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* Nokia Corporation - initial contribution.
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*
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* Contributors:
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*
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* Description: 
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*
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*/
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#include "rsaimpl.h"
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#include "rsafunction.h"
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#include "pluginconfig.h"
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#include <cryptopanic.h>
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#include <cryptostrength.h>
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#include <securityerr.h>
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using namespace SoftwareCrypto;
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/* CRSAImpl */
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CRSAImpl::CRSAImpl(
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	TUid aCryptoMode,
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	TUid aPadding) :
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	CAsymmetricCipherImpl(aCryptoMode, aPadding)
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	{
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	}
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CRSAImpl* CRSAImpl::NewL(const CKey& aKey, TUid aCryptoMode, TUid aPadding)
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	{
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	CRSAImpl* self = CRSAImpl::NewLC(aKey, aCryptoMode, aPadding);
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	CleanupStack::Pop(self);
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	return self;
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	}
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CRSAImpl* CRSAImpl::NewLC(const CKey& aKey, TUid aCryptoMode, TUid aPadding)
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	{
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	CRSAImpl* self = new(ELeave) CRSAImpl(aCryptoMode, aPadding);
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	CleanupStack::PushL(self);
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	self->ConstructL(aKey);
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	return self;
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	}
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CRSAImpl::~CRSAImpl()
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	{
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	}
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TInt CRSAImpl::GetMaximumOutputLengthL() const
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	{
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	const TInteger& N = iKey->GetBigIntL(KRsaKeyParameterNUid);
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	if (iCryptoMode.iUid == KCryptoModeDecrypt)
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		return N.ByteCount() - iPadding->MinPaddingLength();
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	else
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		return N.ByteCount();
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	}
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TInt CRSAImpl::GetMaximumInputLengthL() const
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	{
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	const TInteger& N = iKey->GetBigIntL(KRsaKeyParameterNUid);
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	if (iCryptoMode.iUid == KCryptoModeEncrypt)
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		return N.ByteCount() - iPadding->MinPaddingLength();
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	else
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		return N.ByteCount();
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	}
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void CRSAImpl::ConstructL(const CKey& aKey)
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	{
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	const TInteger& N = aKey.GetBigIntL(KRsaKeyParameterNUid);
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	TCrypto::IsAsymmetricWeakEnoughL(N.BitCount());
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	CAsymmetricCipherImpl::ConstructL(aKey);
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	if (! IsValidKeyLengthL(N.ByteCount()))
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		{
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		User::Leave(KErrKeySize);
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		}
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	}
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CExtendedCharacteristics* CRSAImpl::CreateExtendedCharacteristicsL()
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	{
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	// All Symbian software plug-ins have unlimited concurrency, cannot be reserved
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	// for exclusive use and are not CERTIFIED to be standards compliant.
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	return CExtendedCharacteristics::NewL(KMaxTInt, EFalse);
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	}
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const CExtendedCharacteristics* CRSAImpl::GetExtendedCharacteristicsL()
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	{
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	return CRSAImpl::CreateExtendedCharacteristicsL();
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	}
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TUid CRSAImpl::ImplementationUid() const
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	{
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	return KCryptoPluginRsaCipherUid;
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	}
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void CRSAImpl::EncryptL(const TDesC8& aInput, TDes8& aOutput) const
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	{
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	__ASSERT_DEBUG(aOutput.MaxLength() >= GetMaximumOutputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));
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	__ASSERT_DEBUG(aInput.Length() <= GetMaximumInputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicInputTooLarge));
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	HBufC8* buf = HBufC8::NewLC(GetMaximumOutputLengthL());
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	TPtr8 ptr = buf->Des();
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	iPadding->PadL(aInput, ptr);
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	RInteger input = RInteger::NewL(ptr);
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	CleanupStack::PushL(input);
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	RInteger output;
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	RSAFunction::EncryptL(*iKey, input, output);
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	CleanupStack::PushL(output);
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	aOutput.Append(*(output.BufferLC()));
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	CleanupStack::PopAndDestroy(4, buf); //BufferLC, output, input, buf
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	}
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void CRSAImpl::DecryptL(const TDesC8& aInput, TDes8& aOutput) const
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	{
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	__ASSERT_DEBUG(aOutput.MaxLength() >= GetMaximumOutputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicOutputDescriptorOverflow));
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	__ASSERT_DEBUG(aInput.Length() <= GetMaximumInputLengthL(), User::Panic(KCryptoPanic, ECryptoPanicInputTooLarge));
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	RInteger input = RInteger::NewL(aInput);
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	CleanupStack::PushL(input);
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	RInteger output;
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	RSAFunction::DecryptL(*iKey, input, output);
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	CleanupStack::PushL(output);
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	TPtrC8 ptr = *(output.BufferLC());
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	iPadding->UnPadL(ptr, aOutput);
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	CleanupStack::PopAndDestroy(3, &input); //BufferLC(), output, input
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	}
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void CRSAImpl::ProcessL(const TDesC8& aInput, TDes8& aOutput)
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	{
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	if (iCryptoMode.iUid == KCryptoModeEncrypt)
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		{
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		EncryptL(aInput, aOutput);
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		}
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	else
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		{
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		DecryptL(aInput, aOutput);
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		}
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	}
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TBool CRSAImpl::IsValidKeyLengthL(TInt aKeyBytes) const
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	{
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	if (aKeyBytes < 1)
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		return EFalse;
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	switch (iCryptoMode.iUid)
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		{
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		case KCryptoModeEncrypt:
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			// Check if GetMaximumInputLengthL() makes sense,
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			// if not the key length must be too small
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			if (GetMaximumInputLengthL() <= 0)
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				return EFalse;
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			break;
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		case KCryptoModeDecrypt:
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			// Check if GetMaximumOutputLengthL() makes sense,
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			// if not the key length must be too small
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			if (GetMaximumOutputLengthL() <= 0)
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				return EFalse;
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			break;
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		}
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	return ETrue;
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	}
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