<?xml version="1.0" encoding="utf-8"?>+
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<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->+
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<!-- This component and the accompanying materials are made available under the terms of the License +
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"Eclipse Public License v1.0" which accompanies this distribution, +
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and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->+
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<!-- Initial Contributors:+
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    Nokia Corporation - initial contribution.+
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Contributors: +
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-->+
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<!DOCTYPE concept+
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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">+
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<concept id="GUID-1AA392CB-F638-5D35-993E-4A26D67A7C98-GENID-1-12-1-26-1-1-9-1-5-1-8-1" xml:lang="en"><title>How+
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to retrieve characteristics</title><prolog><metadata><keywords/></metadata></prolog><conbody>+
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<p>The following example demonstrates the use of the legacy selector to retrieve+
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the characteristics of an asymmetric cipher object. In the example, an implementation+
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object is constructed (making use of an RSA Key Pair also generated by the+
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framework) and returned. The plug-in characteristics and extended characteristics+
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associated with the object are then accessed. </p>+
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<codeblock id="GUID-CF2DF77C-90BD-56A0-A27D-89C4DA18EDCD-GENID-1-12-1-26-1-1-9-1-5-1-8-1-2-2" xml:space="preserve">#include &lt;cryptoasymmetriccipherapi.h&gt;+
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#include &lt;cryptokeypairgeneratorapi.h&gt;+
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#include &lt;cryptospidef.h&gt;+
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#include &lt;plugincharacteristics.h&gt;+
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#include &lt;extendedcharacteristics.h&gt;+
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#include &lt;keypair.h&gt;+
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+
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// Constant definition for the RSA key pair generator exponent value+
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const TInt KKeyExponent = 65537;+
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+
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using namespace CryptoSpi;+
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+
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// Create a new CCryptoParams instance to contain the RSA Key Pair initialization data+
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CCryptoParams* keyParams = CCryptoParams::NewLC(); +
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                    +
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// Create an RSA Key Pair and Key Pair Generator object pointers+
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CKeyPair* keyPair = NULL;+
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CKeyPairGenerator * keypairImpl = NULL;                +
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                +
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// Set the RSA Key Pair Generator initialization parameters reate an RSA key pair+
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keyParams-&gt;AddL(KKeyExponent, KRsaKeyParameterEUid);+
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keyParams-&gt;AddL(KRsaPrivateKeyStandard, KRsaKeyTypeUid);+
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+
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// Retrieve an instance of an RSA Key Pair Generator implementation from the framework+
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CKeyPairGeneratorFactory::CreateKeyPairGeneratorL( keypairImpl,+
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                                                   KRSAKeyPairGeneratorUid,+
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                                                   keyParams);+
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                                            +
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CleanupStack::PushL(keypairImpl);+
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    +
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// Create an RSA Key Pair    +
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keypairImpl-&gt;GenerateKeyPairL(1024, *keyParams, keyPair);+
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                +
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CleanupStack::PushL(keyPair);+
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                                        +
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// Create and initialize a pointer for the asymmetric cipher implementation object        +
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CAsymmetricCipher* asymmetricCipherImpl = NULL;+
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+
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// If successful, the 'CreateAsymmetricCipherL' method returns KErrNone and sets the +
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// asymmetricCipherImpl pointer to point to the constructed implementation+
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TRAPD(err, CAsymmetricCipherFactory::CreateAsymmetricCipherL(asymmetricCipherImpl,+
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                                                             KRsaCipherUid,+
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                                                             keyPair-&gt;PrivateKey(),+
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                                                             KCryptoModeEncryptUid,+
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                                                             KPaddingModeNoneUid,+
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                                                             NULL));+
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+
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// Having successfully constructed the asymmetric cipher implementation object, +
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// it is possible to retrieve the plug-in characteristics associated with it+
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if (asymmetricCipherImpl &amp;&amp; (err == KErrNone))+
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 {+
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 CleanupStack::PushL(asymmetricCipherImpl);+
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+
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 // Retrieving common and algorithm-specific characteristics+
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 // Create a constant pointer of type TCharacteristics used to access the+
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 // asymmetric cipher plug-in's common and algorithm-specific characteristics+
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    const TCharacteristics* chars(NULL);+
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+
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 // Retrieve the common and algorithm-specific characteristics by calling the+
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 // 'GetCharacteristicsL' method passing in TCharacteristics pointer+
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 asymmetricCipherImpl-&gt;GetCharacteristicsL(chars);+
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+
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 // Static cast the characteristics to type TAsymmetricCipherCharacteristics+
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 const TAsymmetricCipherCharacteristics* asymmetricChars = +
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  static_cast&lt;const TAsymmetricCipherCharacteristics*&gt;(chars);+
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+
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 // Retrieve the common characteristics from the TASymmetricCipherCharacteristics+
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 // object+
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 const TCommonCharacteristics* asymmetricCommonChars = &amp;asymmetricChars-&gt;cmn;+
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+
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    TUid implementationId;+
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    TBool hardwareSupported;+
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    TRomLitC16 creatorName;+
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    TInt maximumKeyLength;+
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    TInt32 supportedPaddingModes;+
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+
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 // Example of extracting asymmetric common characteristics+
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 implementationId.iUid = asymmetricCommonChars-&gt;iImplementationUID;+
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 hardwareSupported = asymmetricCommonChars-&gt;iIsHardwareSupported;+
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 creatorName = *(asymmetricCommonChars-&gt;iCreatorName);+
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+
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 // Example of extracting asymmetric algorithm specific characteristics+
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 maximumKeyLength = asymmetricChars-&gt;iMaximumKeyLength;+
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 supportedPaddingModes = *(asymmetricChars-&gt;iSupportedPaddingModes);+
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+
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 //Retrieving extended characteristics+
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+
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 // Create a constant pointer of type CExtendedCharacteristics used to store and+
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 // access the asymmetric cipher plug-in extended characteristics. Retrieve+
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 // the data by calling the 'GetExtendedCharacteristicsL' method and store the+
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 // returned pointer+
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 const CExtendedCharacteristics* extendedChars =+
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  asymmetricCipherImpl-&gt;GetExtendedCharacteristicsL();+
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+
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 // Const casting the pointer to the CExtendedCharacteristics object allows it to+
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 // be pushed onto the cleanup stack+
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 CExtendedCharacteristics* ncExtendedChars =+
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  const_cast&lt;CExtendedCharacteristics*&gt;(extendedChars);+
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 CleanupStack::PushL(ncExtendedChars);+
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+
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 TInt concurrency;+
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+
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 // Each of the extended characteristics for the particular cryptographic+
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 // implementation can then be accessed by passing the UID value into the+
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 // appropriate 'Get' method+
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 concurrency = extendedChars-&gt;GetTIntCharacteristicL(KConcurrencyTypeUid);+
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 // Alternatively, extended characteristic retrieval can be achieved via the+
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 // ListExtendedCharacteristics() method of the CExtendedCharacteristics Object.+
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 // Using the 'ListExtendedCharacteristics' function returns a pointer to a+
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 // CCryptoParams object, that contains a list of all associated extended+
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 // characteristics+
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 const CCryptoParams* extendedCryptoParams = +
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  extendedChars-&gt;ListExtendedCharacteristics();+
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+
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 TBool exclusiveUse;+
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+
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 // The extended characteristics can then be accessed in much the same way as +
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 // before, making a call to the appropriate 'Get' method with the UID value of the+
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 // required type+
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 exclusiveUse = extendedCryptoParams-&gt;GetTIntL(KExclusiveUseTypeUid);+
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+
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 CleanupStack::PopAndDestroy(2, asymmetricCipherImpl);+
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 }+
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+
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// Pop and destroy the remaining items on the cleanup stack+
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CleanupStack::PopAndDestroy(3,keyParams);+
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    +
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</codeblock>+
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</conbody></concept>+
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