中文摘要：

LIU Guongjun, received his M.S. degree in applied mathematics from Xidian University, Xi＇an, China in 2009. He is currently a Ph.D. candidate of Xidian University. His research interests include network coding, cryptography and information security. Email： liuguangjuns@gmail.com WANG Bin, received his B.S. degree in commun- ication engineering from Xi＇an University of Tech- nology, Xi＇an, China in 2005. Now he is a master- doctor combined program graduate student. His res- earch interests include wireless sensor networks and network coding.