中文摘要：

To whom correspondence should be addressed. E-mail： csfenggy@ 126. com Feng Chaosheng, born in 1971. Ph.D. candidate in University of Electronic Science and Technology of China （UESTC）. He received his M. S. degree from Sichuan Normal University in 2006. As a Ph. D. candidate, he majors in network and information security. His research interests include the security of peer-topeer computing systems and mobile networks, the design of secure protocols, the ruses, and the simulation of prevention of computer vicomputer networks.