ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
XML signature validation in AIR
The following example illustrates a dereferencer for enveloped signatures:
package
{
import flash.events.ErrorEvent;
import flash.events.EventDispatcher;
import flash.security.IURIDereferencer;
import flash.utils.ByteArray;
import flash.utils.IDataInput;
}
public class EnvelopedDereferencer
extends EventDispatcher implements IURIDereferencer
{
private var signedMessage:XML;
}
public function EnvelopedDereferencer( signedMessage:XML )
{
this.signedMessage = signedMessage;
}
public function dereference( uri:String ):IDataInput
{
try
{
if( uri.length != 0 )
{
throw( new Error("Unsupported signature type.") );
}
var data:ByteArray = new ByteArray();
data.writeUTFBytes( signedMessage.toXMLString() );
data.position = 0;
}
catch (e:Error)
{
var error:ErrorEvent =
new ErrorEvent("Ref error " + uri + " ", false, false, e.message);
this.dispatchEvent(error);
data = null;
throw new Error("Reference not resolvable: " + uri + ", " + e.message);
}
finally
{
return data;
}
}
This dereferencer class uses a constructor function with a parameter, signedMessage, to make the enveloped
signature document available to the dereference() method. Since the reference in an enveloped signature always
refers to the root of the signed data, the dereferencer() method writes the document into a byte array and returns it.
Last updated 6/6/2012
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