Passport authentication

Passport authentication lets you to use Microsoft’s passport service to authenticate users of your application. If your users have signed up with passport, and you configure the authentication mode of the application to the passport authentication, all authentication duties are off-loaded to the passport servers.
Passport uses an encrypted cookie mechanism to indicate authenticated users. If users have already signed into passport when they visit your site, they’ll be considered authenticated by ASP.NET. Otherwise they’ll be redirected to the passport servers to log in. When they are successfully log in, they’ll be redirected back to your site
To use passport authentication you have to download the Passport Software Development Kit (SDK) and install it on your server. The SDK can be found at http:// msdn.microsoft.com/library/default.asp?url=/downloads/list/websrvpass.aps. It includes full details of implementing passport authentication in your own applications.