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In this paper we formally study important properties of electronic voting protocols. In particular we are interested in coercion-resistance and receipt-freeness. Intuitively, an election protocol is coercion-resistant if a voter A cannot prove to a potential coercer C that she voted in a particular way. We assume that A cooperates with C in an interactive fashion. Receipt-freeness is a weaker property, for which we assume that A and C cannot interact during the protocol: to break receipt-freeness, A later provides evidence (the receipt) of how she voted. While receipt-freeness can be expressed using observational equivalence from the applied pi calculus, we need to introduce a new relation to capture coercion-resistance. Our formalization of coercion-resistance and receipt-freeness are quite different. Nevertheless, we show in accordance with intuition that coercion-resistance implies receipt-freeness, which implies privacy …