1. Hubei Key Laboratory of Distributed System Security, Hubei Engineering Research Center on Big Data Security, School of Cyber Science and Engineering, Huazhong University of Science and Technology, Wuhan, China
2. Department of Information Sciences and Technology, George Mason University, Fairfax, VA, USA
3. SKLOIS, Institute of Information Engineering, CAS, Beijing, China
4. School of Cryptography, University of Chinese Academy of Sciences, Beijing, China
5. College of William and Mary, Williamsburg, VA, USA
6. Institute for Network Sciences and Cyberspace, Tsinghua University, Beijing, China