SimpleSAML_Utilities::generateID PHP Method

    public static function generateID()
    {
        return SimpleSAML\Utils\Random::generateID();
    }

 /**
  * Start a login operation.
  *
  * @param array $params  Various options to the authentication request.
  */
 public function login(array $params = array())
 {
     if (array_key_exists('KeepPost', $params)) {
         $keepPost = (bool) $params['KeepPost'];
     } else {
         $keepPost = TRUE;
     }
     if (!isset($params['ReturnTo']) && !isset($params['ReturnCallback'])) {
         $params['ReturnTo'] = SimpleSAML_Utilities::selfURL();
     }
     if (isset($params['ReturnTo']) && $keepPost && $_SERVER['REQUEST_METHOD'] === 'POST') {
         $params['ReturnTo'] = SimpleSAML_Utilities::createPostRedirectLink($params['ReturnTo'], $_POST);
     }
     $session = SimpleSAML_Session::getInstance();
     $authnRequest = array('IsPassive' => isset($params['isPassive']) ? $params['isPassive'] : FALSE, 'ForceAuthn' => isset($params['ForceAuthn']) ? $params['ForceAuthn'] : FALSE, 'core:State' => $params, 'core:prevSession' => $session->getAuthData($this->authority, 'AuthnInstant'), 'core:authority' => $this->authority);
     if (isset($params['saml:RequestId'])) {
         $authnRequest['RequestID'] = $params['saml:RequestId'];
     }
     if (isset($params['SPMetadata']['entityid'])) {
         $authnRequest['Issuer'] = $params['SPMetadata']['entityid'];
     }
     if (isset($params['saml:RelayState'])) {
         $authnRequest['RelayState'] = $params['saml:RelayState'];
     }
     if (isset($params['saml:IDPList'])) {
         $authnRequest['IDPList'] = $params['saml:IDPList'];
     }
     $authId = SimpleSAML_Utilities::generateID();
     $session->setAuthnRequest('saml2', $authId, $authnRequest);
     $relayState = SimpleSAML_Module::getModuleURL('core/bwc_resumeauth.php', array('RequestID' => $authId));
     $config = SimpleSAML_Configuration::getInstance();
     $authurl = '/' . $config->getBaseURL() . $this->auth;
     SimpleSAML_Utilities::redirect($authurl, array('RelayState' => $relayState, 'AuthId' => $authId, 'protocol' => 'saml2'));
 }