基于社区发现的改进PBFT共识算法

Improved PBFT Consensus Algorithm Based on Community Discovery

摘要: 共识算法是区块链分布式系统的核心组成部分，它是通过遵循预设流程，使互不信任的节点最终实现数据一致性的关键算法。PBFT共识算法在这一过程中能够容忍一定数量的拜占庭错误节点。大规模区块链网络中，通过PBFT共识算法维护分布式账本的一致性，是区块链系统运行的关键。传统的PBFT共识算法通过多个节点间的交叉验证，防止恶意节点的篡改和欺瞒。然而，这种方式的共识过程复杂，在大规模网络中，共识效率低下，且无法有效应对恶意节点和故障节点的影响，导致网络的稳定性难以保证。本文提出一个基于社区发现的改进PBFT算法，通过节点间交易行为数据构建社交网络，根据节点间的业务关联度，利用Louvain社区发现算法进行社区划分。采用“先社区内共识，后社区间共识”的策略，降低大规模共识中的复杂度。实验结果表明，该算法能够显著降低大规模区块链网络的通信复杂度，缩短达成共识时间，提高系统的吞吐量。

Abstract: The consensus algorithm is the core component of the blockchain distributed system. It is the key algorithm that enables nodes that do not trust each other to ultimately achieve data consistency by following the preset process. The PBFT consensus algorithm can tolerate a certain number of Byzantine fault nodes in this process. In large-scale blockchain networks, maintaining the consistency of distributed ledgers through the PBFT consensus algorithm is the key to the operation of the blockchain system. The traditional PBFT consensus algorithm prevents tampering and deception by malicious nodes through cross-validation among multiple nodes. However, the consensus process of this method is complicated. In large-scale networks, the consensus efficiency is low, and it cannot deal with the influence of malicious nodes and faulty nodes, making it difficult to guarantee the stability of the network. This paper proposes an improved PBFT algorithm based on community discovery, constructs a social network through transaction behavior data between nodes, and uses the Louvain community discovery algorithm to divide communities based on the business correlation between nodes. We adopt the strategy of “consensus within the community first, then consensus between communities” to reduce the complexity of large-scale consensus. Experimental results show that this algorithm can significantly reduce the communication complexity of large-scale blockchain networks, shorten the time to reach consensus, and improve the throughput of the system.