中文摘要：

To whom correspondence should be addressed. E-mail： lantian1029@uestc. edu. cn Lan Tian, born in 1977. He is a Ph.D. candidate in the School of Computer Science and Engineering, Uni- versity of Electronic Science and Technology of China. He received his B.S. and M.S. degrees from Sichuan University in 2000 and 2003 respectively. His research inter- ests include secure multiparty computation, E-commerce security and network security.