Efficient Cleansing in Coercion-Resistant Voting

Coercion resistance is a strong security property of electronic voting that prevents adversaries from forcing voters to vote in a specific way by using threats or rewards. There exist clever techniques aimed at preventing voter coercion based on fake credentials, but they are either inefficient or cannot support features such as revoting without leaking more information than necessary to coercers. One of the reasons is that invalid ballots cast due to revoting or coercion need to be removed before the tallying. In this paper, we propose a coercion-resistant Internet voting scheme that does not require the removal of invalid ballots, hence avoids the leakage of information, but still supports revoting. The scheme is very efficient and achieves linear tallying.