Making code voting secure against insider threats using unconditionally secure MIX schemes and human PSMT protocols

Abstract

It is clear to the public that when it comes to privacy, computers and “secure” communication over the Internet cannot fully be trusted. Chaum introduced code voting as a solution for using a possibly infected-by-malware device to cast a vote in an electronic voting application. He trusted the mail system. However, a conspiracy between the mail system and the recipient of the cast ballots breaks privacy. Considering a t-bounded passive adversary, we remove the trust in the mail. We propose both single and multi-seat elections, using PSMT protocols (SCN 2012) where with the help of visual aids, humans can carry out mod10 addition correctly with a 99% degree of accuracy. We introduce an unconditionally secure MIX based on the combinatorics of set systems.