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<task id="GUID-EFF8D1A1-00D5-5F96-8285-414DC0044AB8" xml:lang="en"><title>Setting

Use Policies</title><shortdesc>A use policy denotes the security check required to use the key.

The use policy associated with the key is of type <codeph>TSecurityPolicy</codeph>.

The policy can be set to check capabilities or the Secure ID associated with

the calling process. The calling process should have a <codeph>WriteUserData</codeph> capability. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

<context id="GUID-4F90AC15-5BC9-4A2A-BD86-D6CF6FD04E47"><p>The following steps explain the process of setting a use policy

for a key:</p></context>

<steps id="GUID-16DDA72F-9BC5-52FB-A3C6-874815ABF9FC-GENID-1-8-1-23-1-1-8-1-5-1-5-1-5-1-4-1-12-1-3-2">

<step id="GUID-89755D62-9A44-5F07-9035-6AA97F701C0C-GENID-1-8-1-23-1-1-8-1-5-1-5-1-5-1-4-1-12-1-3-2-1"><cmd>Create a file system

session using an <codeph>RFs</codeph> object. </cmd>

</step>

<step id="GUID-6A14EBD6-AF2D-5CE8-A232-F04B717CA0B3-GENID-1-8-1-23-1-1-8-1-5-1-5-1-5-1-4-1-12-1-3-2-2"><cmd/>

<info>Create an object of type CUnifiedKeyStore using <xref href="GUID-818689D6-EB99-382E-A435-D9C6C5D464DE.dita#GUID-818689D6-EB99-382E-A435-D9C6C5D464DE/GUID-C7A96153-4179-3B3F-878D-1EAA64A98D39"><apiname>CUnifiedKeyStore::NewL()</apiname></xref> or <xref href="GUID-818689D6-EB99-382E-A435-D9C6C5D464DE.dita#GUID-818689D6-EB99-382E-A435-D9C6C5D464DE/GUID-217FBB3B-CEF5-36F2-A612-EDDA0982053C"><apiname>CUnifiedKeyStore::NewLC()</apiname></xref>. </info>

</step>

<step id="GUID-C8F104CE-E857-5615-B847-E3A33EAF7481-GENID-1-8-1-23-1-1-8-1-5-1-5-1-5-1-4-1-12-1-3-2-3"><cmd/>

<info>Initialise the member functions and keystore using the asynchronous

function <xref href="GUID-818689D6-EB99-382E-A435-D9C6C5D464DE.dita#GUID-818689D6-EB99-382E-A435-D9C6C5D464DE/GUID-6C5D732C-1FD1-3EF0-AC90-87690F891B8D"><apiname>CUnifiedKeyStore::Initialize()</apiname></xref>. </info>

</step>

<step id="GUID-B1DD3DB8-90D9-52F7-96B5-B2AD5AE3E1F8"><cmd/>

<info>List all keys in the keystore using the <xref href="GUID-818689D6-EB99-382E-A435-D9C6C5D464DE.dita#GUID-818689D6-EB99-382E-A435-D9C6C5D464DE/GUID-8B22E1BC-D779-32DC-9C0A-CA37E4C0A81B"><apiname>CUnifiedKeyStore::List()</apiname></xref> function.

Retrieve the handle of the key for which the use policy needs to be set. </info>

</step>

<step id="GUID-6CF7703F-8CAC-5DC6-9F43-7E2EE3F39895-GENID-1-8-1-23-1-1-8-1-5-1-5-1-5-1-4-1-12-1-3-2-5"><cmd/>

<info>Set the use policy for the key using the <xref href="GUID-818689D6-EB99-382E-A435-D9C6C5D464DE.dita#GUID-818689D6-EB99-382E-A435-D9C6C5D464DE/GUID-CC8814B6-569C-3426-A319-BFB631211B07"><apiname>CUnifiedKeyStore::SetUsePolicy()</apiname></xref> function. </info>

</step>

</steps>

<result id="GUID-46A56876-6A07-4E94-9D00-73BC1270CAB4"><p>Use policy is set for the selected key. </p> </result>

<example id="GUID-C2150584-293D-50CE-8DDC-19B4D55D8B0B-GENID-1-8-1-23-1-1-8-1-5-1-5-1-5-1-4-1-12-1-3-4"><title>Example</title> <p>The

following code snippet shows how to set use policy for a key. </p> <codeblock id="GUID-FAD1C292-8E42-5348-B975-3CBA7E8D2820-GENID-1-8-1-23-1-1-8-1-5-1-5-1-5-1-4-1-12-1-3-4-3" xml:space="preserve">// Create a file system session object

RFs iFs;

CleanupClosePushL(&iFs);

...

// Initialise the keystore and member functions

CUnifiedKeyStore* keyStore = CUnifiedKeyStore::NewL(fs);

keyStore->Initialize(iStatus); //iStatus is a TRequestStatus object

...

// Retrieve the handle of the key for which use policy has to be set

TCTKeyAttributeFilter  filter.iUsage = EPKCS15UsageAll;

RPointerArray<CCTKeyInfo> iKeys; // This variable will contain the result of the set use policy operation

keyStore->List(iKeys, filter, iStatus);

...

// Retrieve the key handle of the appropriate key

_LIT(KLabel,”keylabel”);

// Select the key with the label you are looking for

TInt keyIndex;

for (TInt j = 0; j < iKeys.Count(); j++)

    {

    if (iKeys[j]->Label() == KLabel) 

        {

        keyIndex = j;

        break;

        }

    }

...

// Set the use policy

TSecurityPolicy usePolicy;

TUint secureId = 0x101FFFFF;

TCapability caps[3];

caps[0] = ECapabilityWriteUserData;

caps[1] = ECapabilityDRM;

caps[2] = ECapabilityReadUserData;

usePolicy = TSecurityPolicy(TSecureId(secureId), caps[0], caps[1], caps[2]);

keyStore->SetUsePolicy(*iKeys, usePolicy, iStatus);

// Clean up

CleanupStack::PopAndDestroy(); // iFs</codeblock> </example>

</taskbody><related-links>

<link href="GUID-60141F31-6061-5C65-809D-FE7A4F8414F7.dita"><linktext>Set Management

Policies</linktext></link>

</related-links></task>