Abstract: In the cloud manufacturing service scenario,blockchain technology has received extensive attention and witnessed a large number of applications as an effective tool to build a bridge of trust between service providers and consumers.Consensus algorithm is the core technology of blockchain.However,existing consensus algorithms still bear the disadvantages such as high consumption and high latency.For this reason,an improved Practical Byzantine Fault Tolerance (PBFT) algorithm named Q-PBFT based on Quality of Service (QoS) value was proposed.Consensus nodes were selected according to QoS value,and then the three-phase protocol of PBFT algorithm was optimized into a two-phase protocol so as to improve communication effectiveness under the premise of satisfying security.A series of theoretical and experimental analyses had proved the effectiveness of the proposed algorithm.

Key words: cloud manufacturing service, blockchain, quality of service, consensus algorithm, practical Byzantine fault tolerance algorithm

摘要： 区块链技术为云制造服务场景下建立供需方信任桥梁的有效工具,共识算法是区块链的核心技术,鉴于现有共识算法存在消耗大、延时高等缺点,提出一种基于服务质量(QoS)值的改进实用拜占庭容错(PBFT)算法。首先根据QoS值筛选共识节点,然后将PBFT算法的三阶段协议优化为二阶段协议,从而在满足安全性的前提下提高通信效率。通过一系列理论和实验分析证明了所提算法的有效性。

关键词: 云制造服务, 区块链, 服务质量, 共识算法, 实用拜占庭容错算法