分野別セミナー

Asharov, Canetti, and Hazay (Eurocrypt 2011) studied how game-theoretic concepts can be used to capture the cryptographic properties of correctness, privacy, and fairness in two-party protocols in the presence of fail-stop adversaries. Based on their work, we characterize the properties of “two-message” oblivious transfer protocols in terms of game-theoretic concepts. Specifically, we present a single two-player game defined using a two-message OT protocol such that the OT protocol satisfies the cryptographic properties of correctness and privacy in the presence of malicious adversaries if and only if the strategy of honestly following the protocol is in a Nash equilibrium in the game.