1. China Electronics Standardization Institute, Beijing 100007, China
2. College of Computer Science, Beijing University of Technology, Beijing 100124, China
3. Beijing Key Laboratory of Trusted Computing, Beijing 100124, China
4. National Engineering Laboratory for Critical Technologies of Information Security Classified Protection, Beijing 100124, China
5. Automation Engineering Institute, Beijing Polytechnic, Beijing 100176, China
6. School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe, AZ 85287, USA