Yi Ping was born in 1969. He received the B. S. degree in computer science and engineering from the PLA University of Science and Technology, Nanjing, in 1991. He received the M. S. degree in computer science from Tongji University, Shanghai, in 2003. He received the Ph.D. degree in computing and information technology, from Fudan University, China in 2005. Now he is an associate professor. His research interests include mobile computing and ad hoc networks security. E-mail: yiping@sjtu.edu.cn