School of Computer Science;
Nanjing University of Posts and Telecommunications;
Nanjing 210023;
China;
Jiangsu Key Laboratory of Big Data Security and Intelligent Processing;
Nanjing University of Posts and Telecommunications;
Nanjing 210023;
China;
Jiangsu Key Laboratory of Big Data Security and Intelligent Processing;
Nanjing University of Posts and Telecommunications;
Nanjing 210023;
China;
Department of Computer Science;
Colorado School of Mines;
Golden 80401;
U.S.A.;