XMLSecurityDSig::addReference PHP Method

    public function addReference($node, $algorithm, $arTransforms = null, $options = null)
    {
        if ($xpath = $this->getXPathObj()) {
            $query = "./secdsig:SignedInfo";
            $nodeset = $xpath->query($query, $this->sigNode);
            if ($sInfo = $nodeset->item(0)) {
                $this->addRefInternal($sInfo, $node, $algorithm, $arTransforms, $options);
            }
        }
    }

function processDocument()
{
    global $src_file, $target_file, $user_pubkey_file_path, $user_cert_file_path;
    require dirname(__FILE__) . '/xmlseclibs.php';
    if (file_exists($target_file)) {
        unlink($target_file);
    }
    $doc = new DOMDocument();
    $doc->load($src_file);
    $objDSig = new XMLSecurityDSig();
    $objDSig->setCanonicalMethod(XMLSecurityDSig::EXC_C14N);
    $objDSig->addReference($doc, XMLSecurityDSig::SHA1, array('http://www.w3.org/2000/09/xmldsig#enveloped-signature'));
    /* gako pribatu bat behar dugu prozesua burutzeko. orain edozein erabiliko dugu. gero txartelekoarekin ordezkatzeko */
    $objKey = new XMLSecurityKey(XMLSecurityKey::RSA_SHA1, array('type' => 'private'));
    /* if key has Passphrase, set it using $objKey->passphrase = <passphrase> " */
    $objKey->loadKey(dirname(__FILE__) . '/privkey.pem', TRUE);
    $objDSig->sign($objKey);
    /* Add associated public key */
    // $objDSig->add509Cert(file_get_contents(dirname(__FILE__) . '/mycert.pem'));
    // $objDSig->add509Cert(file_get_contents($user_cert_file_path));
    if (!file_exists($user_cert_file_path)) {
        debug('File not found', $user_cert_file_path);
    } else {
        $objDSig->add509Cert($user_cert_file_path);
    }
    $objDSig->appendSignature($doc->documentElement);
    $doc->save($target_file);
}