School of Computer Science, China University of Geosciences, Wuhan 430074, China;
Shandong Provincial Key Laboratory of Computer Network, Jinan 250014, China;
School of Computer Science, China University of Geosciences, Wuhan 430074, China;
Key Laboratory of Network and Information Attack and Defense Technology of Ministry of Education, Beijing University of Posts and Telecommunications, Beijing100876, China;
Department of Information and Communication Technology, University of Agder(UiA), Grimstad, Norway;
