Assinatura digital

Source breakpoint occurred at line 155 of AssinaturaXML.java.
org.apache.xml.security.transforms.TransformationException: Unknown transformation. No handler installed for URI http://www.w3.org/2000/09/xmldsig#enveloped-signature
Original Exception was org.apache.xml.security.transforms.InvalidTransformException: Unknown transformation. No handler installed for URI http://www.w3.org/2000/09/xmldsig#enveloped-signature
	at org.apache.xml.security.transforms.Transforms.addTransform(Unknown Source)
	at br.com.wg.util.certificado.AssinaturaXML.assinar(AssinaturaXML.java:163)

String xmlDados = "meu xml";
    
    
	String arquivoAssinado = "C:\\temp\\assinado\\meuArquivo.xml";

	String tagPrincipalXml = "contato" ;
	String tagSecundariaXml = "interno" ;


	 String keyStoreCliente = "c:\\cert.pfx" ;
	 
	String keyStoreType = "PKCS12" ;
	String keyStorePass = "minha senha" ;

	Document doc = null ;
	String retorno = null ;

	try
	{
	  
	    doc = DOMUtil.parse(new InputSource(new ByteArrayInputStream(xmlDados.getBytes())));

	    AssinaturaXML assinaturaXML = new AssinaturaXML ( doc , keyStoreCliente , keyStoreType , null , keyStorePass ) ;
	    retorno = assinaturaXML.assinar ( tagPrincipalXml , tagSecundariaXml , true, arquivoAssinado ) ;

	    doc = DOMUtil.parse ( arquivoAssinado ) ;
	    assinaturaXML = new AssinaturaXML ( doc , keyStoreCliente , keyStoreType , null , keyStorePass ) ;
	}
	catch ( Exception e )
	{
	    e.printStackTrace () ;
	}
    }