Abstract: With the in-depth application of blockchain technology in industries such as finance and healthcare, the challenges it faces are becoming increasingly prominent. Among them, the optimization and development of consensus mechanisms are the most crucial. Currently, the two consensus protocols are mainly adopted by consortium chains, PBFT and Raft, and both have certain limitations. The communication volume of the PBFT consensus mechanism increases exponentially with the increase in the number of nodes in the blockchain network, leading to a decrease in efficiency. Although the Raft consensus mechanism has been optimized in terms of efficiency, its ability to resist Byzantine attacks is weak. To address these issues, a consensus mechanism MRBFT based on Raft that resists Byzantine attacks is proposed. Firstly, a reputation value mechanism is introduced in the Raft election process. By electing nodes with higher reputation values, the reliability of the elected nodes is enhanced. At the same time, a certain proportion of Monitor nodes are elected along with the Leader. Secondly, during the consensus process, the Monitor nodes supervise the behavior of the other nodes to enhance the algorithm’s ability to resist Byzantine attacks. At the same time, the reputation values of the nodes are updated to ensure that the most trustworthy nodes are elected in each round, improving the security of the algorithm. Experimental results show that, under the same conditions of resisting Byzantine attacks as PBFT, as the number of nodes increases, MRBFT has lower communication volume, with communication overhead being 44% of PBFT and throughput being 1.5 times that of PBFT. Compared with similar algorithms, in scenarios with similar security, it has more obvious optimization effects in terms of throughput and consensus delay.

Key words: blockchain, consensus mechanism, Byzantine attacks, supervisory strategy, reputation value mechanism