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os/security/cryptoplugins/cryptospiplugins/source/softwarecrypto/dhkeypairgenimpl.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. 
     1 /*

     2 * Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of the License "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description: 

    15 *

    16 */

    17 

    18 

    19 #include "dhkeypairgenimpl.h"

    20 #include "pluginconfig.h"

    21 #include "keypair.h"

    22 

    23 using namespace SoftwareCrypto;

    24 using namespace CryptoSpi;

    25 

    26 /* CDHKeyPairGenImpl */

    27 CDHKeyPairGenImpl::CDHKeyPairGenImpl()

    28 	{

    29 	

    30 	}

    31 

    32 CDHKeyPairGenImpl::~CDHKeyPairGenImpl()

    33 	{

    34 	

    35 	}

    36 

    37 CDHKeyPairGenImpl* CDHKeyPairGenImpl::NewL(void)

    38 	{

    39 	CDHKeyPairGenImpl* self = CDHKeyPairGenImpl::NewLC();

    40 	CleanupStack::Pop(self);

    41 	return self;

    42 	}

    43 

    44 CDHKeyPairGenImpl* CDHKeyPairGenImpl::NewLC(void)

    45 	{

    46 	CDHKeyPairGenImpl* self = new(ELeave) CDHKeyPairGenImpl();

    47 	CleanupStack::PushL(self);

    48 	self->ConstructL();

    49 	return self;

    50 	}

    51 

    52 void CDHKeyPairGenImpl::ConstructL(void)

    53 	{

    54 	CKeyPairGenImpl::ConstructL();

    55 	}

    56 

    57 CExtendedCharacteristics* CDHKeyPairGenImpl::CreateExtendedCharacteristicsL()

    58 	{

    59 	// All Symbian software plug-ins have unlimited concurrency, cannot be reserved

    60 	// for exclusive use and are not CERTIFIED to be standards compliant.

    61 	return CExtendedCharacteristics::NewL(KMaxTInt, EFalse);

    62 	}

    63 

    64 const CExtendedCharacteristics* CDHKeyPairGenImpl::GetExtendedCharacteristicsL()

    65 	{

    66 	return CDHKeyPairGenImpl::CreateExtendedCharacteristicsL();

    67 	}

    68 

    69 TUid CDHKeyPairGenImpl::ImplementationUid() const

    70 	{

    71 	return KCryptoPluginDhKeyPairGenUid;

    72 	}

    73 

    74 void CDHKeyPairGenImpl::Reset()

    75 	{

    76 	// does nothing in this plugin

    77 	}

    78 

    79 void CDHKeyPairGenImpl::GenerateKeyPairL(TInt /*aKeySize*/, const CCryptoParams& aKeyParameters, CKeyPair*& aKeyPair)

    80 	{

    81 	/*

    82 	 * unpack the parameters, we're expecting the N and G parameters and if present the x parameter (aka private key)

    83 	 */

    84 	const TInteger& N = aKeyParameters.GetBigIntL(KDhKeyParameterNUid);

    85 	const TInteger& G = aKeyParameters.GetBigIntL(KDhKeyParameterGUid);

    86 

    87 	/*

    88 	 * do some sanity checking

    89 	 */

    90 	RInteger nminus2 = RInteger::NewL(N);

    91 	CleanupStack::PushL(nminus2);

    92 	--nminus2;

    93 	--nminus2;

    94 

    95 	if ((G < TInteger::Two()) || (G > nminus2))

    96 		{

    97 		User::Leave(KErrArgument);

    98 		}

    99 

   100 	/*

   101 	 * has a private key x been supplied? if not then generate it

   102 	 */

   103 	RInteger x;

   104 	if (aKeyParameters.IsPresent(KDhKeyParameterxUid))

   105 		{

   106 		x = RInteger::NewL(aKeyParameters.GetBigIntL(KDhKeyParameterxUid));

   107 		}

   108 		else

   109 		{

   110 		// find a random x | 1 <= x <= n-2

   111 		x = RInteger::NewRandomL(TInteger::One(), nminus2);

   112 		}

   113 	CleanupClosePushL(x);

   114 	/*

   115 	 * generate the public key with X = G^(x) mod N

   116 	 */

   117 	RInteger X = TInteger::ModularExponentiateL(G, x, N);

   118 	CleanupClosePushL(X);

   119 

   120 	/*

   121 	 * create the keys parameters

   122 	  */

   123 	CCryptoParams* publicKeyParameters = CCryptoParams::NewLC();

   124 	publicKeyParameters->AddL(X, KDhKeyParameterXUid);

   125 	TKeyProperty publicKeyProperties = {KDHKeyPairGeneratorUid, 	KCryptoPluginDhKeyPairGenUid, 

   126 									KDHPublicKeyUid, KNonEmbeddedKeyUid };

   127 	CCryptoParams* privateKeyParameters = CCryptoParams::NewLC();

   128 	privateKeyParameters->AddL(x, KDhKeyParameterxUid);

   129 	TKeyProperty privateKeyProperties = {KDHKeyPairGeneratorUid, KCryptoPluginDhKeyPairGenUid,

   130 									KDHPrivateKeyUid, KNonEmbeddedKeyUid };

   131 

   132 	/*

   133 	 * create the public key

   134 	 */

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

   136 	CleanupStack::PushL(publicKey);

   137 

   138 	/*

   139 	 * create the private key

   140 	 */

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

   142 	CleanupStack::PushL(privateKey);

   143 

   144 	/*

   145 	 * create the key pair

   146 	 */

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

   148 	

   149 	/* 

   150 	 * cleanup stack - it should contain nminus2, x (if allocated here), X, publicKeyParameters, privateKeyParameters, publicKey and privateKey

   151 	 */

   152 	CleanupStack::Pop(2, publicKey);

   153 	CleanupStack::PopAndDestroy(5, &nminus2);

   154 	}
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