public function getQRText($label, $secret)
    {
        return 'otpauth://totp/' . rawurlencode($label)
            . '?secret=' . rawurlencode($secret)
            . '&issuer=' . rawurlencode($this->issuer)
            . '&period=' . intval($this->period)
            . '&algorithm=' . rawurlencode(strtoupper($this->algorithm))
            . '&digits=' . intval($this->digits);
    }