Description: The "Longhorn" Identity System provides a unified store and representation for information about people, groups, and devices across all applications, and leverages this information to enable secure communication. In this session, learn how the Identity System enables developers to easily build applications that work across a continuum of secure "digital interaction" scenarios, from server-less person-to-person interactions to server-based organization-to-organization interactions. A detailed demonstration shows how "Longhorn" itself takes advantage of the Identity System for secure file sharing, secure networking over the Internet, and single-sign-on and secure wireless in the home (the "Castle" network).