There's an interesting article on MSDN discussing how security is implemented on Windows Mobile 5.0. Developers working on Windows Mobile version 5.0–based devices, and using Visual Studio 2005, Visual C# and Visual Basic .NET should know about these changes.

Some policies are already known to developers targeting the Windows Mobile Smartphone platform. But now with Windows Mobile 5.0 bringing a unified model, it is interesting to find out how it will work on Pocket PC - even more on Pocket PC Phone Edition devices.

According to the article "... Windows Mobile–based [device] implements a set of security policies that determine whether an application is allowed to run and, if allowed, with what level of trust. To develop an application for a Windows Mobile–based device, developers need to know what the security configuration of a device is. Developers need to know how to sign an application with the appropriate certificate to allow the application to run (and to run with the needed level of trust)".