Improved PBFT Algorithm Based on Reputations Synchronization and Group Consensus

Introducing a reputation mechanism to improve the practical Byzantine fault-tolerant algorithm (PBFT) can effectively increase the security of the system, but the lack of a proper reputation synchronization method can easily lead to malicious behaviors such as node reputation fraud. To solve the above problems, this paper proposes an improved PBFT algorithm (RS-PBFT) which can synchronize node reputation. Firstly, node types are distinguished by node behaviors. The node types represent node reputation status. Secondly, the management node, which summarizes node behavior, judges node type and synchronizes node reputation, is selected by voting method. Finally, the grouping idea is used to optimize the consistency protocol. The consensus between consensus groups is parallel. Furthermore, the consensus within consensus groups is co-dominated by multiple subgroup master nodes, which reduces the communication overhead and solves the problems such as the lack of limit of a single master node. The experimental results show that when the number of consensus nodes is 12, the throughput of RS-PBFT algorithm is 5.98 times that of PBFT algorithm. The consensus delay is reduced to 27.5% of PBFT algorithm, and the communication cost is reduced by 72.6%.