DyBFT: leaderless BFT protocol based on locally adjustable valid committee set mechanism

To guarantee the liveness of Byzantine fault-tolerant state machine replication (BFT-SMR) protocols in asynchronous environments, asynchronous fallback strategies are frequently utilized to replace traditional leader-based view change mechanisms. However, leader-centric protocols have certain limitations: (1) a single leader may create a system bottleneck, making it difficult to guarantee liveness when under attack. (2) transitioning between partially synchronous and asynchronous protocols presents a challenge in achieving a balance between throughput and latency. To solve these problems, this paper proposes DyBFT, a leaderless BFT-based protocol. Each replica replaces the traditional leader election mechanism and dual-path switching mechanism by a scheme that locally adjusts the local valid committee set. The paper presents the implementation of two variations of DyBFT, namely DyBFT1 and DyBFT2. DyBFT1 utilizes parallel path proposals and local block commits without requiring additional communication overhead, effectively mitigating performance degradation resulting from an increase in the number of replicas and transaction volume. DyBFT2 optimizes commit rules to achieve higher throughput, low latency and stability. Experimental results demonstrate that, compared to existing solutions, DyBFT achieves lower latency and higher throughput in large-scale and unpredictable network environments.