abstract: As a result of physically owning the client machine, cheaters in online games currently have the upper-hand when it comes to avoiding detection. To address this problem and turn the table on cheaters, this paper presents Fides, an anomaly-based cheat detection approach that remotely validates game execution. With Fides, a server-side Controller specifies how and when a client-side Auditor measures the game. To accurately validate measurements, the Controller partially emulates the client and collaborates with the server. This paper examines a range of cheat methods and initial measurements that counter them, showing that a Fides prototype is able to efficiently detect several existing cheats, including one state-of-the-art cheat that is advertised as undetectable.  bio: Wu-chang Feng is currently an Associate Professor in the Intel Systems and Networking Laboratory at Portland State University where he leads a research group in networking and security. Wu-chang received his B.S. in 1992 from Penn State University and his M.S.E. and Ph.D. degrees in 1994 and 1999 from the University of Michigan. He was awarded the IEEE Communications Society 2003 William R. Bennett prize as well as one of four prizes recognizing the Best IBM Research Papers in Computer Science, Electrical Engineering and Math published in 2002.