Efficient Vote Authorization in Coercion-Resistant Internet Voting

Some years ago, Juels et al. introduced the first coercion-resistant Internet voting protocol. Its basic concept is still the most viable approach to address voter coercion and vote selling in Internet voting. However, one of the main open issues is its unrealistic computational requirements of the quadratic-time tallying procedure. In this paper, we examine the cause of this issue, namely the authorization of votes, and summarize the most recent proposals to perform this step in linear time. We explain the key underlying concepts of these proposals and introduce a new protocol based on anonymity sets. The size of these anonymity sets serves as an adjustable security parameter, which determines the degree of coercion-resistance. The main advantage of the new protocol is to move computational complexity introduced in recent works from the voter side to the tallying authority side.