Validating detached signature with jsr105

Question

Hi all.
I need to sign a SOAP message and I need to use JSR105. I've created a message with the following code and is signed without problems. However, I can't validate the signature. As you can see the elements that contains the nodes are OMElement (specific for Axis2 SOAP server) that are an instance of Node and Element classes.
The error I get is:
Exception in thread "main" javax.xml.crypto.dsig.XMLSignatureException: javax.xml.crypto.URIReferenceException: com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException: Cannot resolve element with ID 1
     at org.jcp.xml.dsig.internal.dom.DOMReference.dereference(DOMReference.java:366)
     at org.jcp.xml.dsig.internal.dom.DOMReference.validate(DOMReference.java:318)
     at org.jcp.xml.dsig.internal.dom.DOMXMLSignature.validate(DOMXMLSignature.java:230)
     at SignedSoap.main(SignedSoap.java:272)
Caused by: javax.xml.crypto.URIReferenceException: com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException: Cannot resolve element with ID 1
     at org.jcp.xml.dsig.internal.dom.DOMURIDereferencer.dereference(DOMURIDereferencer.java:84)
     at org.jcp.xml.dsig.internal.dom.DOMReference.dereference(DOMReference.java:358)
     ... 3 more
Caused by: com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException: Cannot resolve element with ID 1
     at com.sun.org.apache.xml.internal.security.utils.resolver.implementations.ResolverFragment.engineResolve(Unknown Source)
     at com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolver.resolve(Unknown Source)
     at org.jcp.xml.dsig.internal.dom.DOMURIDereferencer.dereference(DOMURIDereferencer.java:77)
     ... 4 more
javax.xml.crypto.URIReferenceException: com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException: Cannot resolve element with ID 1
     at org.jcp.xml.dsig.internal.dom.DOMURIDereferencer.dereference(DOMURIDereferencer.java:84)
     at org.jcp.xml.dsig.internal.dom.DOMReference.dereference(DOMReference.java:358)
     at org.jcp.xml.dsig.internal.dom.DOMReference.validate(DOMReference.java:318)
     at org.jcp.xml.dsig.internal.dom.DOMXMLSignature.validate(DOMXMLSignature.java:230)
     at SignedSoap.main(SignedSoap.java:272)
Caused by: com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolverException: Cannot resolve element with ID 1
     at com.sun.org.apache.xml.internal.security.utils.resolver.implementations.ResolverFragment.engineResolve(Unknown Source)
     at com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolver.resolve(Unknown Source)
     at org.jcp.xml.dsig.internal.dom.DOMURIDereferencer.dereference(DOMURIDereferencer.java:77)
     ... 4 more
My code is as follows
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Provider;
import java.security.SecureRandom;
import java.util.Calendar;
import java.util.Collections;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dom.*;
import javax.xml.crypto.dsig.dom.*;
import javax.xml.crypto.dsig.keyinfo.*;
import javax.xml.crypto.dsig.spec.C14NMethodParameterSpec;
import javax.xml.soap.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.*;
import org.apache.axiom.om.OMAttribute;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMNamespace;
import org.apache.axiom.om.impl.dom.factory.OMDOMFactory;
import org.apache.xmlbeans.impl.piccolo.xml.XMLStreamReader;
import org.w3c.dom.*;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
//import org.xmlsoap.schemas.soap.encoding.DateTime;
* Construct a SOAP message, sign it and then validate the signature.
* This implementation follows the
* <a ref="http://www.w3.org/TR/SOAP-dsig/">
* W3C Note on digital signatures in SOAP messages
* </a>.
* The validating key is included in the signature.
* DOM Level 2 is used throughout.
* <p>
* The following SOAP message is signed:
* <pre><code>
* <?xml version="1.0" encoding="UTF-8"?>
* <soap-env:Envelope
* xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/">
* <soap-env:Header>
* <SOAP-SEC:Signature
* mustUnderstand="1"
* xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12"/>
* </soap-env:Header>
* <soap-env:Body id="Body">
* <m:GetLastTradePrice xmlns:m="http://wombats.ztrade.com">
* <symbol>SUNW</symbol>
* </m:GetLastTradePrice>
* </soap-env:Body>
* </soap-env:Envelope>
* </code></pre>
public class SignedSoap {
private static boolean debug = false;
public static void main(String[] args) throws Exception {
     int argc = args.length;
     if (argc == 1) {
     if (args[0].equalsIgnoreCase("-help")) {
          System.out.println("Usage: SignedSoap [-debug]");
          System.out.println(" -debug\tactivates debug messages");
          return;
     debug = args[0].equalsIgnoreCase("-debug");
     // Create the SOAP message
     OMDOMFactory omfact=new OMDOMFactory();
     //Node nodo1=fd.newDomNode(options);
     OMNamespace namespace=omfact.createOMNamespace("http://schemas.xmlsoap.org/soap/security/2000-12", "soapenv");
     OMNamespace namespace2=omfact.createOMNamespace("http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd", "wsu");
     OMAttribute attr=omfact.createOMAttribute("mustUnderstand",namespace,"1");
     OMAttribute id=omfact.createOMAttribute("id",namespace,"1");
     OMAttribute id2=omfact.createOMAttribute("id",namespace,"2");
     OMElement sec=omfact.createOMElement("Security", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd","wsse");
     OMElement timestamp=omfact.createOMElement("Timestamp",namespace2);
     OMElement created=omfact.createOMElement("Created",namespace2);
     OMElement expires=omfact.createOMElement("Expires",namespace2);
     created.setText("12122007");
     expires.setText("12122008");
     timestamp.addAttribute(id);
     timestamp.addChild(created);
     timestamp.addChild(expires);
     sec.addChild(timestamp);
     System.out.println("Generating the DOM tree...");
     // Get input source
     org.w3c.dom.Node security = (Node)sec;
     //if (debug) {
     // dumpDOMDocument(root);
     // Generate a DSA key pair
     System.out.println("Generating the DSA keypair...");
     KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
     kpg.initialize(1024, new SecureRandom("not so random".getBytes()));
     KeyPair keypair = kpg.generateKeyPair();
// Assemble the signature parts
     System.out.println("Preparing the signature...");
     String providerName = System.getProperty
("jsr105Provider", "org.jcp.xml.dsig.internal.dom.XMLDSigRI");
     XMLSignatureFactory sigFactory = XMLSignatureFactory.getInstance("DOM",
(Provider) Class.forName(providerName).newInstance());
Reference ref = sigFactory.newReference("#1",
     sigFactory.newDigestMethod(DigestMethod.SHA1, null));
SignedInfo signedInfo = sigFactory.newSignedInfo(
     sigFactory.newCanonicalizationMethod(
          CanonicalizationMethod.INCLUSIVE_WITH_COMMENTS,
          (C14NMethodParameterSpec) null),
sigFactory.newSignatureMethod(SignatureMethod.DSA_SHA1, null),
     Collections.singletonList(ref));
     KeyInfoFactory kif = sigFactory.getKeyInfoFactory();
     KeyValue kv = kif.newKeyValue(keypair.getPublic());
KeyInfo keyInfo = kif.newKeyInfo(Collections.singletonList(kv));
XMLSignature sig = sigFactory.newXMLSignature(signedInfo, keyInfo);
     // Insert XML signature into DOM tree and sign
     System.out.println("Signing the SOAP message...");
     // Find where to insert signature
     Element ts = getFirstChildElement(envelope);
     DOMSignContext sigContext =
     new DOMSignContext(keypair.getPrivate(), sec);
     // Need to distinguish the Signature element in DSIG (from that in SOAP)
     sigContext.putNamespacePrefix(XMLSignature.XMLNS, "ds");
     // register Body ID attribute getNextSiblingElement(
     sigContext.setIdAttributeNS
     (ts,
     "http://schemas.xmlsoap.org/soap/security/2000-12","id");
     sig.sign(sigContext);
     if (debug) {
     dumpDOMDocument(envelope);
     // Validate the XML signature
// Locate the signature element
     Element sigElement = getNextSiblingElement(ts);
// Validate the signature using the public key generated above
DOMValidateContext valContext =
     new DOMValidateContext(keypair.getPublic(), sigElement);
     // register Body ID attribute getNextSiblingElement(
     valContext.setIdAttributeNS
     (ts,
     "http://schemas.xmlsoap.org/soap/security/2000-12","id");
boolean isValid = sig.validate(valContext);
     System.out.println("Validating the signature... " +
     (isValid ? "valid" : "invalid"));
* Outputs DOM representation to the standard output stream.
* @param root The DOM representation to be outputted
private static void dumpDOMDocument(org.w3c.dom.Node root)
     throws TransformerException, TransformerConfigurationException {
     System.out.println("\n");
     // Create a new transformer object
     Transformer transformer =
     TransformerFactory.newInstance().newTransformer();
     transformer.setOutputProperty(OutputKeys.INDENT, "yes");
     // Dump the DOM representation to standard output
     transformer.transform(new DOMSource(root), new StreamResult(System.out));
     System.out.println("\n");
* Returns the first child element of the specified node, or null if there
* is no such element.
* @param node the node
* @return the first child element of the specified node, or null if there
*     is no such element
* @throws NullPointerException if <code>node == null</code>
private static Element getFirstChildElement(org.w3c.dom.Node node) {
     org.w3c.dom.Node child = node.getFirstChild();
     while (child != null &&
     child.getNodeType() != org.w3c.dom.Node.ELEMENT_NODE) {
child = child.getNextSibling();
return (Element) child;
* Returns the next sibling element of the specified node, or null if there
* is no such element.
* @param node the node
* @return the next sibling element of the specified node, or null if there
*     is no such element
* @throws NullPointerException if <code>node == null</code>
public static Element getNextSiblingElement(org.w3c.dom.Node node) {
     org.w3c.dom.Node sibling = node.getNextSibling();
     while (sibling != null &&
     sibling.getNodeType() != org.w3c.dom.Node.ELEMENT_NODE) {
sibling = sibling.getNextSibling();
return (Element) sibling;
Thanks in advance

Answer 1

I've done further advancemets. It seems that the element to feed the sign validator MUST be a document AND that the ID attribute has to be registered in it even if has been already located in inner elements of the message. Now my code looks as follows but I'm not validating the reference. The sign itself can validate though.
The problem is the reference validation. Any ideas? Could it be the prefixes or namespaces? I've been making tests changing both but no luck so far.
Thanks in advance.
package _2006_08.sa.liberty;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Provider;
import java.security.SecureRandom;
import java.util.Calendar;
import java.util.Collections;
import java.util.Iterator;
import javax.xml.crypto.URIDereferencer;
import javax.xml.crypto.URIReference;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dom.*;
import javax.xml.crypto.dsig.dom.*;
import javax.xml.crypto.dsig.keyinfo.*;
import javax.xml.crypto.dsig.spec.C14NMethodParameterSpec;
import javax.xml.soap.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.*;
import org.apache.axiom.om.OMAttribute;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMNamespace;
import org.apache.axiom.om.impl.dom.factory.OMDOMFactory;
import org.apache.xmlbeans.impl.piccolo.xml.XMLStreamReader;
import org.oasis_open.docs.wss._2004._01.oasis_200401_wss_wssecurity_secext_1_0_xsd.SecurityDocument;
import org.w3c.dom.*;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
//import org.xmlsoap.schemas.soap.encoding.DateTime;
* Construct a SOAP message, sign it and then validate the signature.
* This implementation follows the
* <a ref="http://www.w3.org/TR/SOAP-dsig/">
* W3C Note on digital signatures in SOAP messages
* </a>.
* The validating key is included in the signature.
* DOM Level 2 is used throughout.
* <p>
* The following SOAP message is signed:
* <pre><code>
* <?xml version="1.0" encoding="UTF-8"?>
* <soap-env:Envelope
* xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/">
* <soap-env:Header>
* <SOAP-SEC:Signature
* mustUnderstand="1"
* xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12"/>
* </soap-env:Header>
* <soap-env:Body id="Body">
* <m:GetLastTradePrice xmlns:m="http://wombats.ztrade.com">
* <symbol>SUNW</symbol>
* </m:GetLastTradePrice>
* </soap-env:Body>
* </soap-env:Envelope>
* </code></pre>
public class SignedSoap {
private static boolean debug = false;
public static void main(String[] args) throws Exception {
     int argc = args.length;
     if (argc == 1) {
     if (args[0].equalsIgnoreCase("-help")) {
          System.out.println("Usage: SignedSoap [-debug]");
          System.out.println(" -debug\tactivates debug messages");
          return;
     debug = args[0].equalsIgnoreCase("-debug");
     // Create the SOAP message
     System.out.println("Creating the SOAP message...");
     SOAPMessage soapMessage = MessageFactory.newInstance().createMessage();
     SOAPPart soapPart = soapMessage.getSOAPPart();
     SOAPEnvelope soapEnvelope = soapPart.getEnvelope();
     if(soapEnvelope instanceof Source){
          System.out.println("0");
     if(soapEnvelope instanceof Node){
     System.out.println("1");
     if(soapEnvelope instanceof Element){
     System.out.println("2");
     if(soapEnvelope instanceof Document){
          System.out.println("3");
     SOAPHeader soapHeader = soapEnvelope.getHeader();
     SOAPHeaderElement headerElement = soapHeader.addHeaderElement(
soapEnvelope.createName("Signature", "SOAP-SEC",
"http://schemas.xmlsoap.org/soap/security/2000-12"));
     SOAPBody soapBody = soapEnvelope.getBody();
     soapBody.addAttribute(soapEnvelope.createName("id", "SOAP-SEC",
     "http://schemas.xmlsoap.org/soap/security/2000-12"), "1");
     Name bodyName =soapEnvelope.createName("GetLastTradePrice", "m",
     "http://wombats.ztrade.com");
     SOAPBodyElement gltp = soapBody.addBodyElement(bodyName);
     Name name = soapEnvelope.createName("symbol");
     SOAPElement symbol = gltp.addChildElement(name);
     symbol.addTextNode("SUNW");
     // Generate a DOM representation of the SOAP message
     OMDOMFactory omfact=new OMDOMFactory();
     //Node nodo1=fd.newDomNode(options);
     OMNamespace namespace=omfact.createOMNamespace("http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd", "wsu");
     OMNamespace namespace2=omfact.createOMNamespace("http://www.w3.org/2002/12/soap-envelope", "S");
     OMAttribute attr=omfact.createOMAttribute("mustUnderstand",namespace,"1");
     OMAttribute id=omfact.createOMAttribute("Id",namespace2,"1");
     OMAttribute id2=omfact.createOMAttribute("Id",namespace2,"2");
     OMElement sec=omfact.createOMElement("Security", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd","wsse");
     OMElement timestamp=omfact.createOMElement("Timestamp",namespace);
     OMElement created=omfact.createOMElement("Created",namespace);
     OMElement expires=omfact.createOMElement("Expires",namespace);
     OMElement frame=omfact.createOMElement("Framework",namespace2);
     OMElement signa=omfact.createOMElement("Signature",namespace2);
     timestamp.declareDefaultNamespace(namespace.getNamespaceURI());
     timestamp.setNamespace(namespace);
     Calendar now=Calendar.getInstance();
     Calendar exp=Calendar.getInstance();
     exp.add(now.MINUTE, 5);
     System.out.println("test");
     created.setText("created");
     expires.setText("expires");
     System.out.println("test");
     timestamp.addAttribute(id);
     System.out.println("test");
     timestamp.addChild(created);
     timestamp.addChild(expires);
     //sec.addChild(signa);
     sec.addAttribute(id2);
     sec.addChild(timestamp);
     //sec.addChild(frame);
     //System.out.println(sec.getParent().toString());
     System.out.println("Generating the DOM tree...");
     // Get input source
     Source source = soapPart.getContent();
     if(soapPart instanceof Source){
               System.out.println("10");
          if(soapPart instanceof Node){
          System.out.println("11");
          if(soapPart instanceof Element){
          System.out.println("12");
          if(soapPart instanceof Document){
               System.out.println("13");
     //Source source2 = soapPart.getFirstChild();
     //System.out.println(source.toString());
          //javax.xml.stream.XMLStreamReader inSource = sec.getXMLStreamReader();
     DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
     dbf.setNamespaceAware(true);
     DocumentBuilder db = null;
     System.out.println("13");
     //synchronized (dbf) {
          db = dbf.newDocumentBuilder();
          System.out.println("13");
     Document doc = db.newDocument();
     doc.appendChild((Node)sec);
     org.w3c.dom.Node root = (org.w3c.dom.Node) doc.getDocumentElement();
     System.out.println("13");
     System.out.println("13: "+root.getFirstChild().getLocalName());
     org.w3c.dom.Node envelope = (Node)sec;//soapPart.getFirstChild();
/* Node) sec;
     if (source instanceof DOMSource) {
     root = ((DOMSource)source).getNode();
     } else if (source instanceof SAXSource) {
     InputSource inSource = ((SAXSource)source).getInputSource();
     DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
     dbf.setNamespaceAware(true);
     DocumentBuilder db = null;
     synchronized (dbf) {
          db = dbf.newDocumentBuilder();
     Document doc = db.parse(inSource);
     root = (org.w3c.dom.Node) doc.getDocumentElement();
     } else {
     System.err.println("error: cannot convert SOAP message (" +
          source.getClass().getName() + ") into a W3C DOM tree");
     System.exit(-1);
     //if (debug) {
     // dumpDOMDocument(root);
     // Generate a DSA key pair
     System.out.println("Generating the DSA keypair...");
     KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
     kpg.initialize(1024, new SecureRandom("not so random".getBytes()));
     KeyPair keypair = kpg.generateKeyPair();
// Assemble the signature parts
     System.out.println("Preparing the signature...");
     String providerName = System.getProperty
("jsr105Provider", "org.jcp.xml.dsig.internal.dom.XMLDSigRI");
     XMLSignatureFactory sigFactory = XMLSignatureFactory.getInstance("DOM",
(Provider) Class.forName(providerName).newInstance());
Reference ref = sigFactory.newReference("#1",
     sigFactory.newDigestMethod(DigestMethod.SHA1, null));
SignedInfo signedInfo = sigFactory.newSignedInfo(
     sigFactory.newCanonicalizationMethod(
          CanonicalizationMethod.INCLUSIVE_WITH_COMMENTS,
          (C14NMethodParameterSpec) null),
sigFactory.newSignatureMethod(SignatureMethod.DSA_SHA1, null),
     Collections.singletonList(ref));
     KeyInfoFactory kif = sigFactory.getKeyInfoFactory();
     KeyValue kv = kif.newKeyValue(keypair.getPublic());
KeyInfo keyInfo = kif.newKeyInfo(Collections.singletonList(kv));
XMLSignature sig = sigFactory.newXMLSignature(signedInfo, keyInfo);
     // Insert XML signature into DOM tree and sign
     System.out.println("Signing the SOAP message...");
     // Find where to insert signature
     //Element envelope = getFirstChildElement(root);
     Element header = getFirstChildElement(envelope);
     System.out.println("Signing the SOAP message...");
     //System.out.println(header.getLocalName());
     DOMSignContext sigContext =
     new DOMSignContext(keypair.getPrivate(), envelope);
     // Need to distinguish the Signature element in DSIG (from that in SOAP)
     System.out.println("Signing the SOAP message...");
     sigContext.putNamespacePrefix(XMLSignature.XMLNS, "ds");
     // register Body ID attribute getNextSiblingElement(
     sigContext.setIdAttributeNS
     (header,
               "http://www.w3.org/2002/12/soap-envelope","Id");
     System.out.println("Signing the SOAP message...");
     sig.sign(sigContext);
     if (debug) {
     dumpDOMDocument(envelope);
     // Validate the XML signature
     String providerName2 = System.getProperty
("jsr105Provider", "org.jcp.xml.dsig.internal.dom.XMLDSigRI");
XMLSignatureFactory sigFactory2 = XMLSignatureFactory.getInstance("DOM",
(Provider) Class.forName(providerName2).newInstance());
SecurityDocument secdoc=SecurityDocument.Factory.parse(envelope);
System.out.println(secdoc.xmlText());
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
     dbf.setNamespaceAware(true);
     Document doc = dbf.newDocumentBuilder().parse(secdoc.newInputStream());
// Locate the signature element
     //Element sigElement = //getFirstChildElement(header);
          //getNextSiblingElement(header);
// Validate the signature using the public key generated above
     System.out.println(doc.getFirstChild().getLastChild().getLocalName());
     DOMValidateContext valContext = new DOMValidateContext
(keypair.getPublic(), doc.getElementsByTagName("ds:Signature").item(0));
          valContext.setProperty("javax.xml.crypto.dsig.cacheReference", Boolean.TRUE);
          System.out.println(doc.getElementsByTagName("ds:Signature").item(0).getLocalName());
// DOMValidateContext valContext =
     // new DOMValidateContext(keypair.getPublic(), sigElement);
     // register Body ID attribute getNextSiblingElement(
// System.out.println(header.getNamespaceURI());
          //valContext.setIdAttributeNS((Element) doc.
               //     getElementsByTagNameNS("wsu", "Timestamp").item
                    //(0), null, "Id");
          ((Element)doc.getElementsByTagName("wsu:Timestamp").item(0)).setAttributeNS("S", "Id", "1");
          ((Element)doc.getElementsByTagName("wsu:Timestamp").item(0)).setPrefix("wsu");
          valContext.setIdAttributeNS((Element)doc.getElementsByTagName("wsu:Timestamp").item(0),
     "http://www.w3.org/2002/12/soap-envelope","Id");
     //System.out.println(valContext.getElementById("1").getLocalName());
     //valContext.setBaseURI("http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd");
     System.out.println("1");
     XMLSignature signature = sigFactory2.unmarshalXMLSignature(valContext);
     System.out.println("2: "+valContext.getDefaultNamespacePrefix());
     System.out.println(valContext.getElementById("1").getLocalName());
     //System.out.println(header.getLocalName());
     //System.out.println(getNextSiblingElement(header).getLocalName());
     //System.out.println(header.getAttribute("id"));
     //System.out.println(header.getBaseURI());
     if(signature.getSignatureValue().validate(valContext))
     System.out.println("Firma OK");
     Iterator it = signature.getSignedInfo().getReferences().iterator();
if (((Reference) it.next()).validate(valContext))
     System.out.println("ref OK");
boolean isValid = signature.validate(valContext);
     System.out.println("Validating the signature... " +
     (isValid ? "valid" : "invalid"));
* Outputs DOM representation to the standard output stream.
* @param root The DOM representation to be outputted
private static void dumpDOMDocument(org.w3c.dom.Node root)
     throws TransformerException, TransformerConfigurationException {
     System.out.println("\n");
     // Create a new transformer object
     Transformer transformer =
     TransformerFactory.newInstance().newTransformer();
     transformer.setOutputProperty(OutputKeys.INDENT, "yes");
     // Dump the DOM representation to standard output
     transformer.transform(new DOMSource(root), new StreamResult(System.out));
     System.out.println("\n");
* Returns the first child element of the specified node, or null if there
* is no such element.
* @param node the node
* @return the first child element of the specified node, or null if there
*     is no such element
* @throws NullPointerException if <code>node == null</code>
private static Element getFirstChildElement(org.w3c.dom.Node node) {
     org.w3c.dom.Node child = node.getFirstChild();
     while (child != null &&
     child.getNodeType() != org.w3c.dom.Node.ELEMENT_NODE) {
child = child.getNextSibling();
return (Element) child;
* Returns the next sibling element of the specified node, or null if there
* is no such element.
* @param node the node
* @return the next sibling element of the specified node, or null if there
*     is no such element
* @throws NullPointerException if <code>node == null</code>
public static Element getNextSiblingElement(org.w3c.dom.Node node) {
     org.w3c.dom.Node sibling = node.getNextSibling();
     while (sibling != null &&
     sibling.getNodeType() != org.w3c.dom.Node.ELEMENT_NODE) {
sibling = sibling.getNextSibling();
return (Element) sibling;
}