Towards Realising Oblivious Voting

Abstract

Electronic voting machines promise to determine election results more efficiently without sacrificing reliability. Two desirable security properties seem to contradict each other however: First, the voter’s choice is to be kept secret at all costs, even from election officers who set up and administrate the election machine. On the other hand, ballot secrecy should not compromise the correctness of the tally. We present a construction that conceals the voter’s choice even from the voting machine while producing a provably-correct tally. Our scheme is an improvement of Bingo Voting, [1]. To hide the voter’s choice from the voting machine, we conceive of an electro-mechanical physical oblivious transfer (pOT) device. We further use blind commitments, an extension of cryptographic commitments. Blind commitments can jointly be created by a group of entities, while no single entity is aware of the hidden secret. They can later be unveiled in another multi-party computation. This work is an extended version of a conference paper, [2]. In this version, we work out the details of our construction. Our results corroborate the feasibility of an electronic voting machine that is oblivious to the voters’ choices.