Coin Flipping of Any Constant Bias Implies One-Way Functions
We show that the existence of a coin-flipping protocol safe against any non-trivial constant bias (.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 √(2) -1/2 - o(1) ≈ .207. Unlike the result of Haitner and Omri, our result also holds for weak coin-flipping protocols.
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