Free Active Directory Integration and single sign-on for Linux and Mac OS X - Centrify Express is the No. 1 choice of IT professionals for Active Directory-based authentication and single sign-on to cross-platform systems. Centrify Express is not only the quickest and easiEST solution to use and deploy for integrating Linux and Mac systems with Active Directory, but delivers more functionality and more to upgrade to than alternative offerings. And best of all - it is free!