* @param storage
* @return the KeyInfo which is referred to by this KeyInfoReference, or null if can not be resolved
* @throws XMLSecurityException
*/
private KeyInfo resolveReferentKeyInfo(Element element, String baseURI, StorageResolver storage) throws XMLSecurityException {
KeyInfoReference reference = new KeyInfoReference(element, baseURI);
Attr uriAttr = reference.getURIAttr();
XMLSignatureInput resource = resolveInput(uriAttr, baseURI, secureValidation);
Element referentElement = null;
try {