ASP.NET Interview Questions on Passport Authentication

What is Passport Authentication?
Passport authentication identifies users via Microsoft Passport’s single sign-on service. Microsoft Passport is meant to provide Internet users with a single identity that they can use to visit a wide variety of Web sites that require authentication. Information about the user is available to your application through a profile that is stored with Microsoft.

What are the advantages of Passport authentication?
The advantages of Passport authentication are that the user doesn’t have to remember separate user names and passwords for various Web sites and that the user can maintain his or her profile information in a single location. Passport authentication also provides access to other Microsoft services, such as Passport Express Purchase.

What is passport software development kit (passport SDK)?
To use Passport authentication in your Web application, you must install the Passport SDK. The Passport SDK is free for preproduction development and testing. To deploy a site for public use, you must obtain an annual license from Microsoft.

How does Passport authentication work?
When a user accesses an application that implements Passport authentication, ASP.NET checks the user’s machine for a current passport authentication cookie. If none is found, ASP.NET directs the user to a Passport sign-on page. Once the user signs in, the Passport service authenticates the user, stores an authentication cookie on the user’s computer, and directs the user back to the originally requested Web page.

What are the steps to follow to use Passport authentication?
1. Install the Passport SDK. Passport is not included with Visual Studio, although the .NET Framework does include classes for working with the Passport SDK once it is installed.
2. Set the application’s authentication mode to Passport in Web.config. Set authorization to deny unauthenticated users.
3. Use the PassportAuthentication_OnAuthenticate event to access the user’s Passport profile to identify and authorize the user.
4. Implement a sign-out procedure to remove Passport cookies from the user’s machine.

Where is PassportAuthentication_OnAuthenticate event present?
PassportAuthentication_OnAuthenticate event is present in Global.asax.