中文摘要：

XIAO Yuelei, received the B.S. degree from Central South University, Changsha, China in 2001, and the M.S. degree from Xi＇an Jiaotong University, Xi＇an, China in 2005. He is currently a Ph.D. candidate of the Department of Telecommunication Engineering, Xidian University, Xi＇an, China. His research interests focus on security protocols analysis and trusted computing. Email： xiaoyuelei@163.com WANG Yumin, senior member of IEEE. He is currently a Professor in the Department of Telecommunication Engineering, Xidian University, Xi＇an, China. His research interests focus on information theory, coding and cryptography. P ANG Lioojun, received his B.S., M.S. and Ph.D. degrees from Xidian University, Xi＇an, China in 2000, 2003 and 2006 respectively. He is currently an Associate Professor in the School of Life Science and Technology, Xidian University. His research interests focus on threshold mechanisms and cryptography.