Abstract: In business process collaboration,the decentralized mechanism provided by consortium blockchain can ensure the trustworthiness of collaboration processing and data storing.Practical Byzantium Faulty Tolerance (PBFT) consensus algorithm used in consortium blockchain can avoid the consumption of node computing power and better meet the needs of cooperation speed.However,with the increase of the number of nodes,the consensus speed of PBFT will greatly decrease,and nodes cannot dynamically join and leave during the consensus period,which is difficult to meet the dynamic requirements of the process collaboration environment.Therefore,a consensus algorithm based on reputation was proposed to divide nodes into groups.According to the reputation of nodes in business process collaboration,whether nodes could provide reliable and stable consensus services was determined.Only part of nodes was selected for consensus to improve the speed and stability of consensus.At the same time,the mechanism of node dynamic joining and leaving was designed to meet the dynamic requirements of business process collaboration.The experimental results showed that the consensus mechanism could select stable nodes to participate in the consensus,significantly improve the consensus efficiency,and support the joining and leaving of nodes in the normal transaction process.

Key words: business process collaboration, consortium blockchain, dynamic practical Byzantium faulty tolerance, grouping algorithm, reputation model

摘要： 在业务流程协作中,联盟链提供的去中心化机制能够保障协作过程可信以及数据可信。联盟链使用的实用性拜占庭容错共识（PBFT）算法能避免节点算力的消耗,较好地满足了协作速度的需要。然而,随着节点数量增多,PBFT算法的共识速度会大幅下降,而且在共识期间节点不能动态加入和退出,难以满足流程协作环境的动态性需求。为此,设计了一个基于信誉对节点进行分组的共识机制。该机制根据节点在业务流程协作中的信誉来判断节点能否提供可靠、稳定的共识服务,只选出部分节点进行共识,以此提高共识的速度和稳定性。同时,设计了节点动态加入和退出的机制,以满足业务流程协作对动态性的要求。经实验验证,该共识机制能够选取稳定的节点参与共识,显著提高共识效率,并支持节点在正常交易过程中的加入和退出。

关键词: 业务流程协作, 联盟链, 动态PBFT, 分组算法, 信誉模型