# Coin flipping by telephone a protocol for solving impossible problems

@inproceedings{Blum1983CoinFB, title={Coin flipping by telephone a protocol for solving impossible problems}, author={M. Blum}, booktitle={SIGA}, year={1983} }

Alice and Bob want to flip a coin by telephone. (They have just divorced, live in different cities, want to decide who gets the car.) Bob would not like to tell Alice HEADS and hear Alice (at the other end of the line) say "Here goes . . . I'm flipping the coin. . . . You lost!"Coin-flipping in the SPECIAL way done here has a serious purpose. Indeed, it should prove an INDISPENSABLE TOOL of the protocol designer. Whenever a protocol requires one of two adversaries, say Alice, to pick a sequence… Expand

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