He holds a Ph.D. from the University of California, Berkeley, where he discovered serious weaknesses in a number of widely deployed security systems, including those used by cellular phones and wireless networks. He also studied systems for protecting the personal privacy of Internet users, which led to his role as Chief Scientist at Zero-Knowledge Systems (now Radialpoint). His research currently focuses on developing usable and useful technologies to help Internet users maintain their security and privacy. He is a Senior Member of the ACM and a winner of the Early Researcher Award, the Outstanding Young Computer Science Researcher Award, and the Electronic Frontier Foundation's Pioneer Award.