Achieving Meaningful Efficiency in Coercion-Resistant, Verifiable Internet Voting

Abstract: In traditional voting schemes with paper, pens, and ballot-boxes, appropriate procedures are put in place to reassure voters that the result of the tally is correct. Considering that in Internet voting errors or fraud will generally scale over a much greater fraction of votes, the demand to get strong reassurances as well, seems more than justified. With the ambition of offering a maximum degree of transparency, so-called verifiable schemes have been proposed. By publishing the relevant information, each voter may verify that her vote is included in the final tally and that accepted votes have been cast using proper voting material. Remarkably, this can be done while guaranteeing the secrecy of the ballot at the same time. On the negative side, high transparency will generally make it easier for voters to reveal how they voted, e.g., to a coercer. In this paper we propose an Internet voting protocol that is verifiable and simultateously makes it practically impossible for vote buyers or coercers to elicit the voters ' behaviour. We compare its efficiency with existing work under equal degrees of coercion-resistance using an appropriate measure (). The contribution of our scheme lies in its efficiency during the most critical phases of the voting procedure, i.e., vote casting and tallying. Moreover, during these phases, efficiency is insensitive to the desired degree of coercion-resistance.