Using Prêt à Voter in Victorian state elections

The Pret a Voter cryptographic voting system was designed to be flexible and to offer voters a familiar and easy voting experience. In this paper we present a case study of our efforts to adapt Pret a Voter to the idiosyncrasies of elections in the Australian state of Victoria. The general background and desired user experience have previously been described; here we concentrate on the cryptographic protocols for dealing with some unusual aspects of Victorian voting. We explain the problems, present solutions, then analyse their security properties and explain how they tie in to other design decisions. We hope this will be an interesting case study on the application of end-to-end verifiable voting protocols to real elections.