protected function generateChecksumForPage()
    {
        return sha1(
                sprintf("%s|%s|%s|%s|%s|%s|%s|%s", $this->_secretCode, $this->data->merchant, $this->data->status, $this->data->statusCode, $this->data->orderID, $this->data->paymentID, $this->data->reference, $this->data->transactionID
                )
        );
    }