Exact, Efficient and Information-Theoretically Secure Voting with an Arbitrary Number of Cheaters

TL;DR

This paper introduces three polynomial-time voting protocols that ensure unconditional privacy and correctness with any number of cheaters, providing exact tally outputs and enhanced security features, including vote verification and everlasting security.

Contribution

The paper presents novel voting protocols that are deterministic, unconditionally secure, and do not limit the number of dishonest participants, advancing secure voting technology.

Findings

Protocols output exact tallies deterministically

Privacy remains unconditional despite dishonest participants

Enhanced security with vote verification and everlasting security options

Abstract

We present three voting protocols with unconditional privacy and correctness, without assuming any bound on the number of corrupt participants. All protocols have polynomial complexity and require private channels and a simultaneous broadcast channel. Unlike previously proposed protocols in this model, the protocols that we present deterministically output the exact tally. Our first protocol is a basic voting scheme which allows voters to interact in order to compute the tally. Privacy of the ballot is unconditional in the sense that regardless of the behavior of the dishonest participants nothing can be learned through the protocol that could not be learned in an ideal realisation. Unfortunately, a single dishonest participant can make the protocol abort, in which case the dishonest participants can nevertheless learn the outcome of the tally. Our second protocol introduces voting authorities which improves the communication complexity by limiting interaction to be only between voters and authorities and among the authorities themselves; the simultaneous broadcast is also limited to the authorities. In the second protocol, as long as a single authority is honest, the privacy is unconditional, however, a single corrupt authority or a single corrupt voter can cause the protocol to abort. Our final protocol provides a safeguard against corrupt voters by enabling a verification technique to allow the authorities to revoke incorrect votes without aborting the protocol. Finally, we discuss the implementation of a simultaneous broadcast channel with the use of temporary computational assumptions, yielding versions of our protocols that achieve everlasting security.