public function getData()
{
$this->validateParams();
$params = $this->getParamsToSign();
$signer = new Signer($params);
$sign = $signer->signWithRSA($this->privateKey);
$resp['order_string'] = sprintf('%s&sign="%s"&sign_type="RSA"', $signer->getContentToSign(), urlencode($sign));
return $resp;
}