/*

 * 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: 

 * RSA Keypair implementation

 * RSA keypair generation implementation

 *

 */

 /**

  @file

 */

 #include "rsakeypairgenimpl.h"

 #include "pluginconfig.h"

 #include "keypair.h"

 #include <cryptospi/cryptospidef.h>

 #include "common/inlines.h"    // For TClassSwap

 using namespace SoftwareCrypto;

 /* CRSAKeyPairGenImpl */

 CRSAKeyPairGenImpl::CRSAKeyPairGenImpl()

 	{

 	}

 CRSAKeyPairGenImpl::~CRSAKeyPairGenImpl()

 	{

 	}

 CRSAKeyPairGenImpl* CRSAKeyPairGenImpl::NewL(void)

 	{

 	CRSAKeyPairGenImpl* self = CRSAKeyPairGenImpl::NewLC();

 	CleanupStack::Pop(self);

 	return self;

 	}

 CRSAKeyPairGenImpl* CRSAKeyPairGenImpl::NewLC(void)

 	{

 	CRSAKeyPairGenImpl* self = new(ELeave) CRSAKeyPairGenImpl();

 	CleanupStack::PushL(self);

 	self->ConstructL();

 	return self;

 	}

 void CRSAKeyPairGenImpl::ConstructL(void)

 	{

 	CKeyPairGenImpl::ConstructL();

 	}

 CExtendedCharacteristics* CRSAKeyPairGenImpl::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* CRSAKeyPairGenImpl::GetExtendedCharacteristicsL()

 	{

 	return CRSAKeyPairGenImpl::CreateExtendedCharacteristicsL();

 	}

 TUid CRSAKeyPairGenImpl::ImplementationUid() const

 	{

 	return KCryptoPluginRsaKeyPairGenUid;

 	}

 void CRSAKeyPairGenImpl::Reset()

 	{

 	// does nothing in this plugin

 	}

 void CRSAKeyPairGenImpl::GenerateKeyPairL(TInt aKeySize, const CCryptoParams& aKeyParameters, CKeyPair*& aKeyPair)

 	{

 	/*

 	 * extract e

 	 */ 

 	const TInt aKeyType = aKeyParameters.GetTIntL(KRsaKeyTypeUid);

 	const TInt aPublicExponent = aKeyParameters.GetTIntL(KRsaKeyParameterEUid);

 	RInteger e = RInteger::NewL(aPublicExponent);

 	CleanupStack::PushL(e);

 	/*

 	 * calculate p, q, n & d

 	 */ 

 	RInteger p;

 	RInteger q;

 	//these make sure n is a least aKeySize long

 	TInt pbits=(aKeySize+1)/2;

 	TInt qbits=aKeySize-pbits;

 	//generate a prime p such that GCD(e,p-1) == 1

 	for (;;)

 		{

 		p = RInteger::NewPrimeL(pbits,TInteger::ETop2BitsSet);

 		CleanupStack::PushL(p);

 		--p;

 		RInteger gcd = e.GCDL(p);

 		if( gcd == 1 )

 			{

 			++p;

 			gcd.Close();

 			//p is still on cleanup stack

 			break;

 			}

 		CleanupStack::PopAndDestroy(&p);

 		gcd.Close();

 		}

 	//generate a prime q such that GCD(e,q-1) == 1 && (p != q)

 	for (;;)

 		{

 		q = RInteger::NewPrimeL(qbits,TInteger::ETop2BitsSet);

 		CleanupStack::PushL(q);

 		--q;

 		RInteger gcd = e.GCDL(q);

 		if( gcd == 1 )

 			{

 			++q;

 			if( p != q )

 				{

 				gcd.Close();

 				//q is still on cleanup stack

 				break;

 				}

 			}

 		CleanupStack::PopAndDestroy(&q);

 		gcd.Close();

 		}

 	//make sure p > q

 	if ( p < q)

 		{

 		TClassSwap(p,q);

 		}

 	//calculate n = p * q

 	RInteger n = p.TimesL(q);

 	CleanupStack::PushL(n);

 	--p;

 	--q;

 	//temp = (p-1)(q-1)

 	RInteger temp = p.TimesL(q);

 	CleanupStack::PushL(temp);

 	//e * d = 1 mod ((p-1)(q-1))

 	//d = e^(-1) mod ((p-1)(q-1))

 	RInteger d = e.InverseModL(temp);

 	CleanupStack::PopAndDestroy(&temp); //temp

 	CleanupStack::PushL(d);

 	/*

 	 * create private key depending on aKeyType

 	 */ 

 	CCryptoParams* privateKeyParameters = CCryptoParams::NewLC();

 	privateKeyParameters->AddL(n, KRsaKeyParameterNUid);

 	TKeyProperty* privateKeyProperties = NULL;

 	TKeyProperty privateKeyProperties_RsaPrivateKeyCRT = {KRSAKeyPairGeneratorUid, KCryptoPluginRsaKeyPairGenUid,

 									KRsaPrivateKeyCRTUid, KNonEmbeddedKeyUid };

 	TKeyProperty privateKeyProperties_RsaPrivateKeyStandard = {KRSAKeyPairGeneratorUid, KCryptoPluginRsaKeyPairGenUid,

 									KRsaPrivateKeyStandardUid, KNonEmbeddedKeyUid };

 	CCryptoParams*publicKeyParameters = CCryptoParams::NewLC();

 	publicKeyParameters->AddL(n, KRsaKeyParameterNUid);

 	publicKeyParameters->AddL(e, KRsaKeyParameterEUid);

 	TKeyProperty publicKeyProperties = {KRSAKeyPairGeneratorUid, KCryptoPluginRsaKeyPairGenUid,

 									KRsaPublicKeyUid, KNonEmbeddedKeyUid };

 	if (aKeyType == KRsaPrivateKeyCRT)			// cleanup stack contains e, p, q, n, d and privateKeyParameters

 	{

 		/*

 		 * calculate dP, dQ and qInv

 		 */ 

 		//calculate dP = d mod (p-1)

 		RInteger dP = d.ModuloL(p); //p is still p-1

 		CleanupStack::PushL(dP);

 		privateKeyParameters->AddL(dP, KRsaKeyParameterDPUid);

 		CleanupStack::PopAndDestroy(&dP);

 		//calculate dQ = d mod (q-1)

 		RInteger dQ = d.ModuloL(q); //q is still q-1

 		CleanupStack::PushL(dQ);

 		privateKeyParameters->AddL(dQ, KRsaKeyParameterDQUid);

 		CleanupStack::PopAndDestroy(&dQ);

 		++p;

 		++q;

 		//calculate inverse of qInv = q^(-1)mod(p)

 		RInteger qInv = q.InverseModL(p);

 		CleanupStack::PushL(qInv);

 		privateKeyParameters->AddL(qInv, KRsaKeyParameterQInvUid);

 		CleanupStack::PopAndDestroy(&qInv);

 		privateKeyParameters->AddL(p, KRsaKeyParameterPUid);

 		privateKeyParameters->AddL(q, KRsaKeyParameterQUid);

 		privateKeyProperties = &privateKeyProperties_RsaPrivateKeyCRT;

 	}

 	else if (aKeyType == KRsaPrivateKeyStandard)

 	{

 		privateKeyParameters->AddL(d, KRsaKeyParameterDUid);

 		privateKeyProperties = &privateKeyProperties_RsaPrivateKeyStandard;

 	}

 	else

 	{

 		User::Leave(KErrNotSupported);

 	}

 	// cleanup stack contains e, p, q, n, d and privateKeyParameters

 	CKey* privateKey = CKey::NewL(*privateKeyProperties, *privateKeyParameters);

 	CleanupStack::PushL(privateKey);

 	/*

 	 * create public key

 	 */

 	CKey* publicKey = CKey::NewL(publicKeyProperties, *publicKeyParameters);

 	CleanupStack::PushL(publicKey);

 	/*

 	* create the key pair

 	*/

 	aKeyPair = CKeyPair::NewL(publicKey, privateKey);

 	CleanupStack::Pop(2, privateKey); //privateKey and publicKey

 	CleanupStack::PopAndDestroy(7, &e); //e, p, q, n, d, privateKeyParameters and publicKeyParameters

 	}