Faculty of Information Technology Beijing University of Technology Beijing 100124 China;
Faculty of Information Technology Beijing University of Technology Beijing 100124 China;
Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China;
Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China;
Faculty of Information Technology Beijing University of Technology Beijing 100124 China;
Faculty of Information Technology Beijing University of Technology Beijing 100124 China;