基于信誉分类的拜占庭容错共识算法

Byzantine Fault Tolerant Consensus Algorithm Based on Reputation Classification

针对许可区块链场景下实用拜占庭容错(Practical Byzantine Fault Tolerance,PBFT)共识算法通信开销大、主节点选取随意以及吞吐量低等问题,通过引入并优化信誉评分模型(Reputation Scoring Model,RSM)。提出了一种基于信誉分类的拜占庭容错(Byzantine Fault Tolerance Based on Reputation Classification,RCBFT)共识算法。定义RSM,依据节点的历史共识行为所获得的信誉评分排序对参与节点进行动态分类以及分级管理,提出基于信誉分类的多层次节点架构;在可信节点层中随机选取节点来担任主节点,优化主节点选取机制;设计了缓冲节点层类型转换策略(Type Conversion Strategy for Nodes,TCSN),兼顾了环境等非主观因素导致低信誉评分的诚实节点不能参与共识的问题,使得诚实节点尽可能多地参与共识,而拜占庭节点快速下降到最差类型中限制共识权限;RCBFT共识算法还对传统三阶段共识协议进行优化,减少通信开销,在确保容错性的同时能够提高算法性能。实验分析表明,相较于PBFT共识算法,RCBFT共识算法能够提升交易吞吐量,降低通信开销与共识时延。

To deal with the problems of large communication overhead,arbitrary selection of the master node,and the low throughput of the Practical Byzantine Fault Tolerance(PBFT)consensus algorithm in the permissioned blockchain scenario,the Reputation Scoring Model(RSM)is introduced and optimized.A Byzantine Fault Tolerance Based on Reputation Classification(RCBFT)consensus algorithm is proposed.First of all,the RSM is defined,and dynamic classification and hierarchical management of participating nodes are implemented based on the reputation score ranking obtained from the historical consensus behavior of the node,and a multi-level node architecture is proposed based on reputation classification.Then,a node is randomly selected in the trusted node layer layer and used as the master node to optimize the master node selection mechanism;at the same time,the buffer node layer type conversion strategy TCSN is designed,which takes into account the problem caused by non-subjective factors such as the environment that honest nodes with low reputation score cannot participate in consensus,thus allowing the honest nodes to participate in consensus as much as possible and the Byzantine node to drop to the worst type quickly to restrict the consensus authority.Finally,the RCBFT consensus algorithm also optimizes the traditional three-stage consensus protocol to reduce communication overhead and improve algorithm performance while ensuring fault tolerance.Experimental analysis shows that,compared with the PBFT consensus algorithm,the RCBFT consensus algorithm can increase transaction throughput and reduce communication overhead and consensus delay.