Abstract: A facility for conducting a coercion-resistant electronic collection is described. The facility receives from the voter a first voter conformation value. At a later time, the facility receives from the voter an encrypted ballot and a second voter confirmation value. Without regard for the value of the received second voter confirmation value, the facility adds the received ballot to a publicly-available list of cast ballots. After the addition, members of the public are able to verify the addition of the received ballot to the list without being able to determine whether the ballot will be counted. The facility counts the ballot if and only the second voter confirmation value received with the ballot matches the received first voter confirmation value.

Abstract: We present a mathematical construct which provides a cryptographic protocol to (verifiably shuffle) a sequence of (k) modular integers, and discuss its application to secure, universally verifiable, multi-authority election schemes. The output of the shuffle operation is another sequence of (k) modular integers, each of which is the same secret power of a corresponding input element, but the order of elements in the output is kept secret. Though it is a trivial matter for the “shuffler” (who chooses the permutation of the elements to be applied) to compute the output from the input, the construction is important because it provides a linear size proof of correctness for the output sequence (i.e. a proof that it is of the form claimed) that can be checked by one or more arbitrary verifiers. The protocol is shown to be honest-verifier zeroknowledge in a special case, and is computational zeroknowledge in general.