Blockchains and Strategic Secondary Censorship

Abstract

Censorship resistance is widely viewed as a core attribute of distributed ledgers. Censorship resistance refers to the inability to selectively exclude technically valid but undesirable transactions from the blockchain. We examine blockchain censorship in a game-theoretic framework that allows for both primary and secondary censorship. The analysis identifies scenarios in which both inclusion and censorship equilibria can arise. Once an equilibrium with strategic secondary censorship is implemented, it may be hard to revert to inclusion: Censorship equilibria are perfectly coalition-proof if the negative impact of an undesirable transaction on block producers is sufficiently large. These results suggest an expanding role for research into methods shaping censorship resistance at the technical layer.