protected function _getQRCodeUrl($title, $name, $secret)
    {
        if (empty($title)) {
            return 'otpauth://totp/'.rawurlencode($name).'?secret='.$secret;
        } else {
            return 'otpauth://totp/'.rawurlencode($title).':'.rawurlencode($name).'?secret='.$secret.'&issuer='.rawurlencode($title);
        }        
    }