Pairing-Based Anonymous Boardroom Voting Scheme

In this paper, we devise a novel anonymous voting protocol based on bilinear pairings. This protocol can be used by a group of participants to vote for one or more resolutions under the decentralized condition (boardroom voting), at the meantime preserving the privacy of participants. More specifically, in the session key set-up phase, every participant just need to broadcast a single message containing an ephemeral public key and a zero-knowledge proof. In the commitment phase, participants should broadcast the commitment of their votes although the actual votes are not revealed. After that, in the voting phase, every participant should encrypts his or her vote by combining these public keys and his secret session key, and then broadcast it to others. Finally, the voting result can be recovered by multiplying all the votes together. The advantage of our protocol over others lies in the fact that once the session keys have been established, they can be used repeatedly over multiple commitment and voting phases. So it requires just two rounds of broadcasting in every voting process after the first one, rendering it pretty good in terms of round efficiency. More precisely, if a group need to vote for several resolutions in one meeting, our protocol would involve less computational load and bandwidth usage in every vote. In fact, it is better than all the other techniques known. Our protocol is provably secure under the Decision Bilinear Diffie-Hellman assumption and random oracle assumption.