You Lin was born in 1966. He received Ph.D. degree at Dalian University of Technology in 2003. He worked as a post-doctor of Beijing University of Aeronautics and Astronautics from 2004 to 2007. Now he is a professor of Hangzhou Dianzi University and. His main research interests include cryptography, information security and combinatorics. E-mail: mryoulin@gmail.com Xu Maozhi was born in 1962. He received Ph.D. degree at Peking University in 1994. He is a professor of Peking University and the director of Research Center of Cryptographic Engineering, Peking University. His research interests include cryptography, information security.