Secure posting to database?

Hello folks,

There’s a common strategy for posting to a database where a serverside page is called, passing it querystring data, in order to add entries to a database.

This is not secure though, anyone can decompile the .swf and hack the database by calling the serverside page with their own info.

Does anyone know of a secure strategy that does not rely on obfuscation?

Thanks a lot!
sf