1. Guizhou Provincial Key Laboratory of Public Big Data, GuiZhou University, Guizhou Guiyang, P. R. China. 61997525@qq.com
2. Information Security Center, Beijing University of Post and Telecommunications, Beijing, P. R. China. leimin@bupt.edu.cn
3. School of Computer Science, China University of Geosciences, Wuhan, P. R. China. weirencs@cug.edu.cn
4. School of Computing Science, University of East Anglia, Norwich, UK. E.Ren@uea.ac.uk
5. Jiangsu Engineering Center of Network Monitoring, School of Computer and Software, Nanjing University of Information Science and Technology, Nanjing, P. R. China. qzghhh@126.com