WCF Services can be accessed from Silver Light version 4 applications. Windows authentication, which means that windows credentials are automatically used without asking the user for login, can be used to provide secure access to the WCF Services which are being accessed from Silver light apps.
To configure Windows authentication for a WCF service use:
After configuring the WCF service to use windows authentication, you can access the service from Silver Light directly as we do it from other applications. No special code is required to do this externally.
Silver Light 4 does not provide any set of special mechanisms to set the mode of authentication to “Windows” when accessing WCF Services. We can only set the authentication mode at the networking level either through HTTPWebRequest or WebClient. In such cases, the required credentials will be provided by the browser or the underlying operating system.