os/security/crypto/weakcryptospi/source/asymmetric/dh.cpp
author sl
Tue, 10 Jun 2014 14:32:02 +0200
changeset 1 260cb5ec6c19
permissions -rw-r--r--
Update contrib.
     1 /*
     2 * Copyright (c) 2003-2010 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 <asymmetric.h>
    20 #include <asymmetrickeys.h>
    21 #include <cryptospi/keys.h>
    22 #include "keyconverter.h"
    23 #include <cryptospi/cryptokeyagreementapi.h>
    24 #include <cryptospi/cryptospidef.h>
    25 
    26 using namespace CryptoSpi;
    27 
    28 CKeyAgreement* GetKeyAgreementCryptoInterfaceLC(TUid aKeyAgreementAlgoUid,
    29 	  CKey& aPrivateKey, CCryptoParams* aParams)
    30 	{
    31 	CKeyAgreement* keyAgreementImpl =  0;
    32 	CKeyAgreementFactory::CreateKeyAgreementL(keyAgreementImpl,
    33 												aKeyAgreementAlgoUid, aPrivateKey,
    34 												aParams);
    35 	CleanupStack::PushL(keyAgreementImpl);
    36 	return keyAgreementImpl;
    37 	}
    38 
    39 EXPORT_C CDH* CDH::NewL(const CDHPrivateKey& aPrivateKey)
    40 	{
    41 	CDH* self = CDH::NewLC(aPrivateKey);
    42 	CleanupStack::Pop(self);
    43 	return self;
    44 	}
    45 
    46 EXPORT_C CDH* CDH::NewLC(const CDHPrivateKey& aPrivateKey)
    47 	{
    48 	CDH* self = new (ELeave) CDH(aPrivateKey);
    49 	CleanupStack::PushL(self);
    50 	return self;
    51 	}
    52 
    53 EXPORT_C HBufC8* CDH::AgreeL(const CDHPublicKey& aPublicKey) const
    54 	{
    55 	/*
    56 	 * both DH keys (ie our private and their public keys) must use the same N and G parameters
    57 	 */
    58 	if ((aPublicKey.N() != iPrivateKey.N()) || (aPublicKey.G() != iPrivateKey.G()))
    59 		{
    60 		User::Leave(KErrArgument);
    61 		}
    62 
    63 	CKey* privateKey = KeyConverter::CreateKeyL(iPrivateKey);
    64 	CleanupStack::PushL(privateKey);
    65 
    66 	/*
    67 	 *  package the common parameters N and G into a crypto params array
    68 	 * we've already checked that both the private and public keys have the 
    69 	 * same N and G so we only need build this array once for both creating 
    70 	 * and calling the interface
    71 	 */
    72 	CCryptoParams* keyParameters = CCryptoParams::NewLC();
    73 	keyParameters->AddL(aPublicKey.N(), KDhKeyParameterNUid);
    74 	keyParameters->AddL(aPublicKey.G(), KDhKeyParameterGUid);
    75 
    76 	/* 
    77 	 * get a DH key agreement interface
    78 	 */
    79 	CKeyAgreement* keyAgreementImpl =  GetKeyAgreementCryptoInterfaceLC(KDHAgreementUid, *privateKey, keyParameters);
    80 
    81 	/* 
    82 	 * call the api to get a DH agreed key
    83 	 */
    84 	CKey* publicKey = KeyConverter::CreateKeyL(aPublicKey);
    85 	CleanupStack::PushL(publicKey);
    86 
    87 	CKey* agreedKey = keyAgreementImpl->AgreeL(*publicKey, keyParameters);
    88 	CleanupStack::PushL(agreedKey);
    89 
    90 	/*
    91 	 * extract the agreed key
    92 	 */
    93 	const TInteger& agreedKeyData = agreedKey->GetBigIntL(KSymmetricKeyParameterUid);
    94 	HBufC8 *agreedKeyToReturn = agreedKeyData.BufferLC();
    95 	CleanupStack::Pop(agreedKeyToReturn);
    96 
    97 	/* 
    98 	 * cleanup stack - it should contain privateKey, keyAgreementImpl, publicKey, keyParameters and agreedKey
    99 	 */
   100 	CleanupStack::PopAndDestroy(5, privateKey);
   101 
   102 	return agreedKeyToReturn;
   103 	}
   104 
   105 EXPORT_C CDH::CDH(const CDHPrivateKey& aPrivateKey) : iPrivateKey(aPrivateKey)
   106 	{
   107 	}