public function getSPcert()
    {
        $cert = null;

        if (isset($this->_sp['x509cert']) && !empty($this->_sp['x509cert'])) {
            $cert = $this->_sp['x509cert'];
        } else {
            $certFile = $this->_paths['cert'].'sp.crt';

            if (file_exists($certFile)) {
                $cert = file_get_contents($certFile);
            }
        }
        return $cert;
    }