Voting with unconditional privacy: CFSY for booth voting

Abstract. We adapt the Cramer, Franklin, Schoenmaker and Yung internet voting proto-col[12] to the booth setting. In this protocol, expressions of the form gr0g x1 1 · · · g xl l (mod q) are used to define an unconditionally hiding commitment scheme. Because of their homo-morphic properties, they are particularly suited for voting protocols with unconditional pri-vacy. In fact, a survey shows that almost all these protocols use, or could benefit from, these commitments. Though not novel cryptographically speaking, the protocol presented is interesting from a voting perspective, because it is simple enough to be understood by non-cryptographers, yet has many desirable properties, such as unconditional privacy, correctness under the discrete log assumption, individual and universal verifiability, and (optionally) bal-lot casting assurance. In addition, we discuss interesting relations to and/or simplifications, of several other protocols, such as the booth voting protocol of Moran and Naor[15], Split