Coin Flipping of Any Constant Bias Implies One-Way Functions

Abstract: We show that the existence of a coin-flipping protocol safe against any non-trivial constant bias (e.g., .499), implies the existence of one way functions. This improves upon a recent result of Haitner and Omri [FOCS ’11], who proved this implication for protocols with bias ~.207. Unlike the result of Haitner and Omri, our result holds also for weak coin-flipping protocols.

Joint work with Iftach Haitner and Aris Tentes.