SG-FCB: A Stackelberg Game-Driven Fair Committee-Based Blockchain Consensus Protocol

Abstract

Committee-based blockchain consensus is a fusion of permissionless consensus and the permissioned Byzantine Fault- Tolerant (BFT) classical protocol. However, three enduring challenges remain: the formal framework for the Proof-of-Stake (PoS)-based hybrid consensus, the dynamic adjustment of committee size and the definition of consensus time-bound. To tackle these challenges, in this paper, we present a Stackelberg game-driven fair committee-based blockchain consensus protocol, dubbed SG-FCB, which combines PoS and reputation-based blockchain hybrid BFT consensus. The SG-FCB protocol lever-ages an unbiased BLS-threshold signature and a random shuffle algorithm to achieve fair leader election and committee reconfiguration seamlessly. Specifically, the variant-BFT is designed to maintain the low communication cost of$\mathcal{O}(n)$, and a Stackelberg game-based incentive mechanism is proposed to jointly maximize the individual profit of the validators and the expected consensus committee responsiveness efficiency of blockchain user. Rigorous security analysis shows that for an adversary with a stakeholding fraction less than 1/3 and sufficient reputation value, we define the time bound for consensus, and the SG-FCB protocol achieves consistency and liveness properties by reasonably setting a corruption parameter and liveness parameter within a formal framework.