Single Sign On (SSO) for cross-domain Asp.net applications, Part-I - The design blue print

Introduction"Yet another Monday morning at your office. Just started to wonder how fast the weekend just passed away, and how hard are the days going to be in this week. You got a mail! Oh no, not a lucrative job offer. Its just another requirement from your new client. Your client has a number of Asp.net of sites, and all he wants is to enable his users to log onto all sites just by logging into