FSM\uff1aFull Selfish Mining Attack on Blockchain

As the number of blockchain miners increases, mining profits become stable and miners\u2019 behaviors become increasingly rational. Mining attacks aim to provide the adversary with unfair additional profits through certain strategies. Selfish mining attack is the most influential blockchain mining attack method, in which the adversary temporarily retains the blocks they discover and strategically releases them, to increase his own profits and waste other miners\u2019 computing power. However, in the existing selfish mining attack methods, only the adversary\u2019s strategy is considered, the strategy that can be adopted by the honest miners is ignored. Those methods just assume that the honest miners will persist mining all the time. While in fact, honest miners also can ensure their profits by choosing appropriate strategies when under attack. We find that when the adversary launches selfish mining attack, honest miners have different expected mining profits in various blockchain states. We prove our finding and conclude that honest miners can improve their profits by intermittent mining (persist mining in non-fork state and stop mining in equal-length fork state) even when their expected mining profit is negative. Based on the above findings and conclusions, we further expand the strategy space of selfish mining and propose a new mining attack strategy - Full Selfish Mining (FSM), in which the adversary can increase his profit by making the blockchain in equal-length fork state as much as possible. The experimental results show that the adversary can increase his revenue by controlling just over 22\\% of the total mining power, and can even launch a 51\\% attack with as little as 28\\% of the total mining power.