How to authenticate client application for trust of messages sent from it

Question

The basic question
How do I know that it is my publicly accessible (client) application that is sending my service messages? How do I know that it is j

Answer 1

Presumably, your server is creating the web page that the Silverlight application sits in. You could create a short-lived temporary "key" that only that web page contains. When the Silverlight app starts up, it reads this key and uses it. Because the server itself has a constantly changing, very short list of allowed keys, you can be more sure that only your app is accessing your services.