Mark Lillibridge is a member of the research staff at Compaq's Systems Research Center (formerly DEC SRC), located in downtown Palo Alto. He received his Ph.D. in Computer Science from Carnegie Mellon University in 1997. He is currently studying the security issues that arise in systems composed of networked home computers; for example, how can free riding be prevented and can such systems provide anonymity to their users? His past work has focused on the design of programming languages. He can be reached at firstname.lastname@example.org.