College of Information Engineering,Yangzhou University,Yangzhou,225127,China;
Division of Computer Science,University of Aizu,Aizu-Wakamatsu,9658580,Japan;
College of Computer Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing,211106,China;
College of Information and Communication Engineering,Harbin Engineering University,Harbin,150001,China;
Department of Computer Software Engineering,Soonchunhyang University,Asan,Korea;
Covert channels; information hiding; data compression; distributed system;