- Construct a Query String (QS) with required parameters (including the web service method name itself (e.g. method=RegUserInfo)
- DES encrypt the Query String with the supplied EncryptKey and obtain the encrypted query string (q)
- Build an MD5 hash according to (QS) and other parameters to form a signature (s)
- Use HTTP POST request to call the web service.
- Obtain the resulting XML response.