A Game Theory Based Rational Mining Strategy in Blockchains With Multiple Rational Miners

Previous researches have shown that a miner using selfish mining strategy is not necessarily profitable if the selfish mining rate is not large enough. In such situation, a miner will choose honest mining strategy rather in order to earn more rewards. Such miners are called rational miners. In this paper, we discuss mining strategies in the blockchains with one honest and two independent rational miners. The rewards earned by different miners using different mining strategy combinations are calculated by the analytical models proposed in previous works. Payoff matrices are constructed and the Nash equilibria are then found by comparing the earned rewards. Numerical results show that the miners have their own dominant strategies in most situations. However, when the mining rates of the two rational miners are both between 0.22 and 0.25, there is no dominant strategy such that the miners shall guess which strategy will be used by the other miner. We proposed a game theory based rational mining strategy that chooses the mining strategy according to a probability distribution. Rewards earned by the proposed strategy are shown to be guaranteed larger than or equal to those earned by honest mining strategy.