An efficient rational secret sharing scheme based on the Chinese remainder theorem
ACISP'11 Proceedings of the 16th Australasian conference on Information security and privacy
Efficient rational secret sharing in standard communication networks
TCC'10 Proceedings of the 7th international conference on Theory of Cryptography
Rational secret sharing with semi-rational players
International Journal of Grid and Utility Computing
Sequential rationality in cryptographic protocols
ACM Transactions on Economics and Computation - Inaugural Issue
Fairness in the presence of semi-rational parties in rational two-party secure computation
International Journal of Grid and Utility Computing
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The problem of carrying out cryptographic computations when the participating parties are rational in a game-theoretic sense has recently gained much attention. One problem that has been studied considerably is that of rational secret sharing. In this setting, the aim is to construct a mechanism (protocol) so that parties behaving rationally have incentive to cooperate and provide their shares in the reconstruction phase, even if each party prefers to be the only one to learn the secret.Although this question was only recently asked by Halpern and Teague (STOC 2004), a number of works with beautiful ideas have been presented to solve this problem. However, they all have the property that the protocols constructed need to know the actual utility values of the parties (or at least a bound on them). This assumption is very problematic because the utilities of parties are not public knowledge. We ask whether this dependence on the actual utility values is really necessary and prove that in the basic setting, rational secret sharing cannot be achieved without it. On the positive side, we show that by somewhat relaxing the standard assumptions on the utility functions, it is possible to achieve utility independence. In addition to the above, observe that the known protocols for rational secret sharing that do not assume simultaneous channels all suffer from the problem that one of the parties can cause the others to output an incorrect value. (This problem arises when a party gains higher utility by having another output an incorrect value than by learning the secret itself; we argue that such a scenario is not at all unlikely.) We show that this problem is inherent in the non-simultaneous channels model, unless the actual values of the parties' utilities from this attack is known, in which case it is possible to prevent this from happening.