Boardroom Voting: Practical Verifiable Voting with Ballot Privacy Using Low-Tech Cryptography in a Single Room

Résumé

A boardroom election is an election that takes place in a single room — the boardroom — in which all voters can see and hear each other. We present the first practical protocol for boardroom elections with ballot privacy and voter verifiability that uses only low-tech cryptography'' without any computers. The protocol combines several practical building blocks in novel ways, including existing ones (e.g., invisible and revealing inks, ink stamps, scales) and a few we introduce. These new building blocks include foldable ballots’’ that can be rotated to obfuscate the alignment of ballot choices with voting marks, and ``visual secrets’’ that are easy to remember but hard to describe. Although closely seated participants in a boardroom election have limited privacy, the protocol ensures that no one can determine how any individual voted. Moreover, each voter can verify that their ballot was correctly cast, collected, and counted, without being able to prove how they voted, providing assurance against undue influence. In contrast with traditional paper ballot voting methods typically used in today’s boardrooms, our protocol provides an alternative that offers higher outcome integrity and ballot privacy while remaining usable and paper based.