Abstract. In this paper, we develop methods for constructing votebuying/coercion attacks on end-to-end voting systems, and describe votebuying/coercion attacks on three proposed end-to-end voting systems: Punchscan, Prˆet-`a-voter , and ThreeBallot. We also demonstrate a different attack on Punchscan, which could permit corrupt election officials to change votes without detection in some cases. Additionally, we consider some generic attacks on end-to-end voting systems.