Department of Computer Science and Engineering,Shanghai Jiaotong University,Shanghai 200240,China;
School of Information Security Engineering,Shanghai Jiaotong University,Shanghai 200240,China;
State Key Laboratory of Information Security,Graduate School of the Chinese Academy of Sciences,Beijing 100039,China;
Distributed and Embedded Security Group,Faculty of EEMCS,University of Twente,7500 AE Enschede,the Netherlands;