1. School of Cyberspace Security, Xi'an University of Posts and Telecommunications, Xi'an, China
2. School of Cyber Engineering, Xidian University, Xi'an, China
3. Key Laboratory of Information Security of Network Systems, College of Mathematics and Computer Science, Fuzhou University, Fuzhou, Fujian, China
4. Department of Information Systems and Cyber Security, The University of Texas at San Antonio, San Antonio, TX, USA
5. Chongqing Key Laboratory of Image Cognition, Chongqing University of Posts and Telecommunications, Chongqing, China