XMLSecurityDSig::sign PHP Method

    public function sign($objKey, $appendToNode = null)
    {
        // If we have a parent node append it now so C14N properly works
        if ($appendToNode != null) {
            $this->resetXPathObj();
            $this->appendSignature($appendToNode);
            $this->sigNode = $appendToNode->lastChild;
        }
        if ($xpath = $this->getXPathObj()) {
            $query = "./secdsig:SignedInfo";
            $nodeset = $xpath->query($query, $this->sigNode);
            if ($sInfo = $nodeset->item(0)) {
                $query = "./secdsig:SignatureMethod";
                $nodeset = $xpath->query($query, $sInfo);
                $sMethod = $nodeset->item(0);
                $sMethod->setAttribute('Algorithm', $objKey->type);
                $data = $this->canonicalizeData($sInfo, $this->canonicalMethod);
                $sigValue = base64_encode($this->signData($objKey, $data));
                $sigValueNode = $this->createNewSignNode('SignatureValue', $sigValue);
                if ($infoSibling = $sInfo->nextSibling) {
                    $infoSibling->parentNode->insertBefore($sigValueNode, $infoSibling);
                } else {
                    $this->sigNode->appendChild($sigValueNode);
                }
            }
        }
    }

 /**
  * @param \DOMNode $parent
  * @param \AerialShip\LightSaml\Meta\SerializationContext $context
  * @return \DOMNode
  */
 function getXml(\DOMNode $parent, SerializationContext $context)
 {
     $objXMLSecDSig = new \XMLSecurityDSig();
     $objXMLSecDSig->setCanonicalMethod($this->getCanonicalMethod());
     $key = $this->getXmlSecurityKey();
     switch ($key->type) {
         case \XMLSecurityKey::RSA_SHA256:
             $type = \XMLSecurityDSig::SHA256;
             break;
         case \XMLSecurityKey::RSA_SHA384:
             $type = \XMLSecurityDSig::SHA384;
             break;
         case \XMLSecurityKey::RSA_SHA512:
             $type = \XMLSecurityDSig::SHA512;
             break;
         default:
             $type = \XMLSecurityDSig::SHA1;
     }
     $objXMLSecDSig->addReferenceList(array($parent), $type, array(Protocol::XMLSEC_TRANSFORM_ALGORITHM_ENVELOPED_SIGNATURE, \XMLSecurityDSig::EXC_C14N), array('id_name' => $this->getIDName(), 'overwrite' => FALSE));
     $objXMLSecDSig->sign($key);
     $objXMLSecDSig->add509Cert($this->getCertificate()->getData(), false, false);
     $firstChild = $parent->hasChildNodes() ? $parent->firstChild : null;
     if ($firstChild && $firstChild->localName == 'Issuer') {
         // The signature node should come after the issuer node
         $firstChild = $firstChild->nextSibling;
     }
     $objXMLSecDSig->insertSignature($parent, $firstChild);
 }