1 Department of Information and Communication Engineering, School of Informatics, Xiamen University, Xiamen, China.
2 Strategic Centre for Research in Privacy-Preserving Technologies and Systems, Nanyang Technological University, Singapore, Singapore.
3 Strategic Centre for Research in Privacy-Preserving Technologies and Systems, Nanyang Technological University, Singapore, Singapore. kwokyan.lam@ntu.edu.sg.
4 School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore. kwokyan.lam@ntu.edu.sg.
5 Pillar of Information Systems Technology and Design, Singapore University of Technology and Design, Singapore, Singapore.
6 Department of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore.
7 School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore.
8 Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, USA.