1. School of Cyber Engineering, Xidian University, Xi’an, China
2. State Key Laboratory of Integrated Service Networks, School of Cyber Engineering, Xidian University, Xi’an, China
3. Department of Information Systems and Cyber Security, The University of Texas at San Antonio, San Antonio, TX, USA
4. Henan Key Laboratory of Network Cryptography Technology, Zhengzhou, China
5. School of Information Systems, Singapore Management University, Bras Basah, Singapore