Towards Rational Consensus in Honest Majority
Varul Srivastava, Sujit Gujar · 2024
Rational Consensus (RC) is a more realistic modelling of the traditional Byzantine Consensus problem, motivated by the recent works in Rational Cryptography. RC is the problem of achieving consensus in the presence of Rational, Byzantine and Honest players (players- participants in the consensus protocol) in a distributed system. This work focuses on consensus in multiple rounds with additional agreement on ordering among rounds which is a more general problem called Atomic BroadCast (ABC). Blockchains is an example of application of ABC. This work abstracts rational players in three types on their incentive structure. We show the impossibility of achieving consensus for two out of the three types of rational players under some conditions. For the third type of rational players, existing work models a single round of agreement and, therefore, doesn't capture the existence of another insecure equilibrium strategy for rational players. We finally fill the gap in the literature of a Rational ABC by proposing a novel protocol for rational consensus, namely pRFT. We prove (i) the correctness of the protocol and (ii) the communication complexity of pRFT, which is a form of accountable protocol, equals the best-known accountable agreement protocols.