1. School of Electronic and Information Engineering, Soochow University, Soochow, China
2. Department of Information and Communication Engineering, School of Informatics, Xiamen University, Xiamen, China
3. Department of Electrical and Computer Engineering, Western University, London, Canada
4. Fujian Provincial Key Laboratory of Network Security and Cryptology and the College of Computer and Cyber Security, Fujian Normal University, Fuzhou, China
5. School of Electronics and Computer Science, University of Southampton, Southampton, U.K.