Improving and Simplifying a Variant of Prêt à Voter
Ralf Küsters, Tomasz Truderung, and Andreas Vogt
Recently, Xia et al. proposed a variant of Pret a Voter which enjoys several attractive properties. Their protocol is among the few verifiable and receipt-free paper-based voting protocols resistant against randomization attacks. Trust is distributed among several authorities and the voter interface is relatively simple. Also, approval and ranked elections are supported. In this paper, we improve and simplify the protocol by Xia et al. Among others, we propose a simpler way of producing ballots, which only involves the encryption and re-encryption of candidate names; homomorphic encryption and proxy re-encryption are not needed. Also, no machine involved in the production of ballots needs to store a secret key. Moreover, unlike the protocol by Xia et al., in our protocol all authorities can be held accountable in case they misbehave in an observable way.