function _getExtension($id, $cert = NULL, $path = NULL)
    {
        $extensions = $this->_extensions($cert, $path);

        if (!is_array($extensions)) {
            return false;
        }

        foreach ($extensions as $key => $value) {
            if ($value['extnId'] == $id) {
                return $value['extnValue'];
            }
        }

        return false;
    }