To whom correspondence should be addressed. E-mail : weiguozhang@ vip. qq. com Zhang Weiguo, received the B. S. degree in management and Ph. D. degree in cryptography from Xidian University, Xi' an, China, in 2001 and 2007, respectively. In 2007, he joined ISN Lab (State Key Laboratory of Integrated Service Networks) at Xidian University. His research interests include cryptogra- phy, sequence design, and coding theory.