XMLSecurityDSig::generateGUID PHP Method

    static function generateGUID($prefix = 'pfx')
    {
        $uuid = md5(uniqid(mt_rand(), true));
        $guid = $prefix . substr($uuid, 0, 8) . "-" . substr($uuid, 8, 4) . "-" . substr($uuid, 12, 4) . "-" . substr($uuid, 16, 4) . "-" . substr($uuid, 20, 12);
        return $guid;
    }

 public function addReference($name, $node, $type)
 {
     if (!$node instanceof DOMNode) {
         throw new Exception('$node is not of type DOMNode');
     }
     $curencdoc = $this->encdoc;
     $this->_resetTemplate();
     $encdoc = $this->encdoc;
     $this->encdoc = $curencdoc;
     $refuri = XMLSecurityDSig::generateGUID();
     $element = $encdoc->documentElement;
     $element->setAttribute("Id", $refuri);
     $this->references[$name] = array("node" => $node, "type" => $type, "encnode" => $encdoc, "refuri" => $refuri);
 }