中文摘要：

LIN Guoyuan, was born in the year of 1975. He is now an associate professor at China University of Mining and Technology. He obtained his Ph.D. from Nanjing University in 2011. His research interests are information and network security, cloud computing security. WANG Danru, is now a postgraduate at China Uni- versity of Mining and Technology, Xuzhou, China, She received the B.Eng. in School of Computer Science and Technology at China University of Mining and Technology in 2012. Her main research interests include information system security, access control and cloud computing. BIE Yuyu. is now a postgraduate at China University of Mining and Technology, Xuzhou, China. She received the B.Eng. in School of Computer Science and Technology at China University of Mining and Technology in 2011. Her main research interests include information system security, access control and cloud computing. LEI Min, male, born in January 1979, received his Ph.D. degree in information security from Beijing University of Posts and Telecommunications（BUPT）. He received a M.S. degree in software engineering and theory in 2002 from BUPT and a BEng degree in computer science in 1999 from Nanchang University. Currently as a lecturer at the School of Computer Science BUPT, his research interests are watermarking, information hiding and information security.