Stefan Saroiu is a senior researcher in the Mobility and Networking Research group at Microsoft Research (MSR) in Redmond. Stefan's research interests span mobile systems, computer security, and distributed systems. With his colleagues at MSR, he has designed and built the reference implementation of a software-based Trusted Platform Module (TPM), which is used in many smartphones and tablets on the market today. Before joining MSR in 2008, Stefan spent three years as an Assistant Professor at the University of Toronto, and four months at Amazon.com as a visiting researcher where he worked on the early designs of their new shopping cart system (aka Dynamo). Stefan received his Ph.D. from the University of Washington where he was co-advised by Steve Gribble and Hank Levy.