Note on fair coin toss via Bitcoin
arXiv:1402.3698
Abstract
In this short note we show that the Bitcoin network can allow remote parties to gamble with their bitcoins by tossing a fair or biased coin, with no need for a trusted party, and without the possibility of extortion by dishonest parties who try to abort. The superfluousness of having a trusted party implies that there is no house edge, as is the case with centralized services that are supposed to generate a profit.
See also https://bitcointalk.org/index.php?topic=277048.0