Competing (Semi-)Selfish Miners in Bitcoin

Francisco J. Marmolejo Cossío, Eric Brigham, Benjamin Sela, Jonathan Katz

Abstract: The Bitcoin protocol prescribes certain behavior by the miners who are responsible for maintaining and extending the underlying blockchain; in particular, miners who successfully solve a puzzle, and hence can extend the chain by a block, are supposed to release that block immediately. Eyal and Sirer showed, however, that a selfish miner is incentivized to deviate from the protocol and withhold its blocks under certain conditions. The analysis by Eyal and Sirer, as well as in followup work, considers a single selfish miner (who may control a large fraction of the hashing power in the network) interacting with a remaining pool of honest miners. Here, we extend this analysis to the case where there are multiple (non-colluding) selfish miners. We find that in this setting there are cases in which it may be profitable for those miners to deviate even when they would not be incentivized to deviate individually.