Publicly Auditable Elections

The talk argues that hardening election systems is necessary but cannot be enough, so detection through auditing must also be part of the plan. The speaker separates two audit types. Administrative audits, such as risk-limiting audits, are run by officials against physical paper ballots. Public audits can be run by anyone, at any time tallies are released, and check results against the votes voters actually cast, so they need no paper. The speaker claims a public audit can catch any alteration of tallies, including attacks not yet invented.

The mechanism is end-to-end verifiability. Each vote is published as a cryptographic commitment that is bound to the choice but reveals nothing about it. Voters receive a confirmation code they can check on a website or ignore, and anyone can verify that the published commitments add up to the announced totals. Tallying works by multiplying encrypted ballots together, so only addition is needed, followed by a proof of correct decryption. A card trick illustrates how a voter can gain confidence in a hidden vote without being able to prove it to anyone else. The talk also mentions deployed systems and a newer commitment-based variant that needs no keys.

The takeaway is that only a small fraction of voters need to check their receipts for high statistical confidence, and each voter chooses whom to trust. The speaker says internet voting is not yet ready, even with these techniques.