code: protected function makeSign($signStr)
      {
          switch ($this->signType) {
              case 'RSA':
                  $rsa = new RsaEncrypt($this->rsaPrivateKey);
  
                  $sign = $rsa->encrypt($signStr);
                  break;
              case 'RSA2':
                  $rsa = new Rsa2Encrypt($this->rsaPrivateKey);
  
                  $sign = $rsa->encrypt($signStr);
                  break;
              default:
                  $sign = '';
          }
  
          return $sign;
      }
docs: 签名算法实现
  @param string $signStr
  @return string
  @author helei