March 1, 2021Yackolley Amoussou Guenou (CEA)
In most committee-based blockchains, participants propose blocks and then exchange messages, so that a block is accepted if a majority of participants sent the corresponding message.
In this presentation, we will present a game theoretic analysis of committee-based blockchains (which run distributed Byzantine fault tolerant consensus) when participants exhibit strategic or adversarial behaviour. All participants are rational and play best responses. Strategic participants maximize expected net rewards, while adversaries goal is to prevent the consensus.
We show that the prescribed protocol is not an equilibrium, and that there exist equilibria without consensus, even when there are few adversaries. However, under given conditions, there exists an equilibrium satisfying the consensus properties.