1. College of Mathematics and Computer Science, Shanxi Normal University, Linfen 041000, China
2. Fujian Provincial Key Laboratory of Network Security and Cryptology, Fujian Normal University, Fuzhou 350007, China
3. School of Computer Science and Mathematics, Fujian University of Technology, Fuzhou 350118, China
4. Guangxi Key Laboratory of Trusted Software, Guilin University of Electronic Technology, Guilin 541004, China
5. College of Mathematics and Informatics, Fujian Normal University, Fuzhou 350118, China