Improving End-to-End Verifiable Voting Systems with Blockchain Technologies

End-to-end verifiable (E2E) voting systems attempt to establish elections where each voter receives direct assurance that their vote was cast correctly, and anyone may determine that each ballot was correctly included in the overall tally of the vote. One such E2E implementation, Helios, achieves this “open audit” functionality by making public the auditing algorithm and each encrypted vote, along with their encryption proofs, on a public bulletin board. Unfortunately, hosting the bulletin board on a centralized server puts this functionality at risk of denial of service or data tampering, each of which could degrade the public's trust of the election results. To mitigate these risks, this paper demonstrates the replacement of the bulletin board concept with decentralized storage and a blockchain. In doing so, the election audit data benefit from a system where such data becomes immutable, and where the data is replicated and publicly accessible. This architecture allows the encrypted votes, their proofs, and the election audit algorithm to be hosted independent of the election services, eliminating the risk of tampering or denial of service while still maintaining voter verifiability.