About the Authentication API

Authentication involves user validation before any information exchange takes place. When a client initiates a request to the server that has authentication enabled, the server challenges the client to confirm its identity. Typically, this amounts to inspecting the name and password of the user account under various authentication protocols. For any given interaction, both client and server must adhere to one agreed protocol.

The server uses the authentication plug-in component to validate user identity. Windows Media Services comes bundled with several plug-in components. The Windows Media Services authenticators are COM-based objects. Using the Windows Media Services Authentication API, you can create a new authenticator with ease. You can also seamlessly integrate it with a server running Windows Media Services to check client credentials against any pre-installed or custom-made user account databases, and to notify the server of the outcome.

Each authenticator is designed to implement one type of authentication. Although there can be more than one authenticator registered in the system, only one authenticator can be used at a time.

Windows Media Services require that a COM component support the free-threading (COINIT_MULTITHREADED) model. Thus, when creating an authentication component, you must avoid using the apartment-threading (COINIT_APARTMENTHREADED) model for the authentication component. While providing better performance and greater flexibility, the free-threading concurrency model lacks thread-safe features. Therefore, as the creator of the COM component, you are responsible for serializing the access to calls to the methods of the object. For more information on the concurrency control in COM, see COM and ActiveX Objects in the Microsoft Platform Software Development Kit (SDK) documentation.