Multi-Leader Byzantine Fault Tolerance in Blockchain: Performance and Security

Byzantine Fault Tolerance (BFT) protocols are a critical research area in distributed systems and blockchain consensus due to their capacity to deliver high throughput and low latency. Traditional BFT protocols typically rely on a single leader to propose transactions and aggregate votes, which often creates a bottleneck due to the leader’s limited communication and computational capacities. The introduction of multi-leader BFT has the potential to mitigate this issue by increasing system parallelism. However, existing approaches fail to address the challenge of electing multiple leaders and lack a comprehensive analysis of the relationship between the number of leaders, security constraints, and system throughput. In this paper, we study the performance and security of multi-leader BFT protocols. Initially, we introduce a secret multi-leader election method resistant to corruption attacks where selected leaders’ identities remain unknown to others until they proposes transactions. Then, we present specific multi-leader BFT constructions that support a pipelined processing methods, realizing high processing parallelism and optimized throughput. Besides, a cross-leader view-change mechanism is designed for multi-leader BFT to enable efficient replacement of malicious leaders. Furthermore, we analyze the impact of the number of leaders on security and demonstrate that our proposals meet the required security standards. Experimental results reveal that the system achieves a throughput of up to 101 ktx/sec with 128 nodes, highlighting the potential of multi-leader BFT to significantly enhance the performance of blockchain systems.