Licensing in a Silverlight 4 application

Does anyone have any experience or suggestions for providing basic licensing support for a Silverlight 4 application?

I'm especially interested in the case where the application is running out-of-browser. I'd like t开发者_Go百科o be able to provide some sort of time-limited licensing option in this case.

One option I've considered is implementing some sort of licensing web service to be called from the application.

Any other suggestions?

While calling a web service would solve the problem of users tampering with files and registry settings it does mean that anyone using your application would need to be connected to the internet to use it.

One way round this is to allow restricted functionality if the application can't connect to the web service, though this might frustrate your users.

You could store the last contact date somewhere (file or registry) and allow full functionality if less than 3 days have elapsed and reduced functionality otherwise. However, this then gets back to having the problem that users could find the file/registry entry and tamper with it to allow full access.

Wassup HullCitySteve! I've been through this myself recently and implemented my own licensing.

But I need to take it a step further in terms of robustness/features so I'm currently trialling CrytpLicensing for .NET, which seems to support Silverlight as well as WPF applications, control libraries or frameworks. Also comes with a ready-made licensing server.

tah-ta!