He received the B.S. degree in precision instruments from Tsinghua University, Beijing, China, the M.S. degree in signal processing from the University of Science and Technology of China, Graduate School at Beijing, China, and the Ph.D. degree in information technology from George Mason University, VA, USA, in 1996, 1999, and 2004, respectively. His research interests include wireless and mobile security, software and network security, fraud detection, and user online safety and privacy. His research has been funded by National Science Foundation, National Security Agency, and Army Research Office/Lab. He received NSF Career Award in 2007 and a Google Faculty Research Award in 2013. More details of his research can be found in http://www.cse.psu.edu/~sxz16/.