1. Guangdong Province Key Laboratory of Information Security Technology, Ministry of Education Key Laboratory of Machine Intelligence and Advanced Computing, School of Computer Science and Engineering, Sun Yat-sen University, Guangzhou, China
2. Institute of Information Engineering, State Key Laboratory of Information Security, Chinese Academy of Sciences, Beijing, China
3. Department of Computer and Information Science, University of Macau, Macau, China
4. Guangdong Key Laboratory of Intelligent Information Processing and the Shenzhen Key Laboratory of Media Security, Shenzhen University, Shenzhen, China