[论文解读] A Survey on Consortium Blockchain Consensus Mechanisms

Wei Yao, Junyi Ye+2 more|arXiv (Cornell University)|Feb 24, 2021

Blockchain Technology Applications and Security参考文献 51被引用 25

一句话总结

本文综述了联盟链中的共识机制，分析了PBFT和HotStuff等协议在容错性、可扩展性和性能方面的表现。比较了它们的运行机制，突出显示PBFT的二次方复杂度和HotStuff的线性复杂度，为企业的区块链部署提供了权衡洞察。

ABSTRACT

Blockchain is a distributed ledger that is decentralized, immutable, and transparent, which maintains a continuously growing list of transaction records ordered into blocks. As the core of blockchain, the consensus algorithm is an agreement to validate the correctness of blockchain transactions. For example, Bitcoin is a public blockchain where each node in Bitcoin uses the Proof of Work (PoW) algorithm to reach a consensus by competing to solve a puzzle. Unlike a public blockchain, a consortium blockchain is an enterprise-level blockchain that does not contend with the issues of creating a resource-saving global consensus protocol. This paper highilights several state-of-the art solutions in consensus algorithms for enterprise blockchain. For example, the HyperLedger by Linux Foundation includes implementing Practical Byzantine Fault Tolerance (PBFT) as the consensus algorithm. PBFT can tolerate a range of malicious nodes and reach consensus with quadratic complexity. Another consensus algorithm, HotStuff, implemented by Facebook Libra project, has achieved linear complexity of the authenticator. This paper presents the operational mechanisms of these and other consensus protocols, and analyzes and compares their advantages and drawbacks.

研究动机与目标

• 分析专为企业级联盟链设计的最新共识算法。
• 评估共识协议中容错性、性能与计算复杂度之间的权衡。
• 比较PBFT与HotStuff的运行机制，重点关注可扩展性与效率。
• 提供对Hyperledger和Libra等企业区块链实际部署的全面概述。

提出的方法

• 调查并分析企业区块链平台中使用的共识算法，包括PBFT和HotStuff。
• 研究PBFT的运行机制，其通过二次方通信复杂度实现拜占庭容错。
• 分析HotStuff，一种基于领导者的协议，通过三阶段投票过程实现线性通信复杂度。
• 基于容错性、消息复杂度和性能特征对比共识机制。
• 评估实际部署案例，如Hyperledger采用PBFT以及Facebook的Libra采用HotStuff。

实验结果

研究问题

• RQ1 PBFT与HotStuff在共识机制和通信复杂度方面有何不同？
• RQ2 联盟链共识协议中，容错性与计算效率之间的权衡是什么？
• RQ3 为何尽管存在二次方复杂度，PBFT仍适用于许可环境？
• RQ4 HotStuff如何实现线性复杂度，相较于PBFT有何优势？

主要发现

• PBFT提供强大的拜占庭容错能力，但通信复杂度为二次方，限制了可扩展性。
• HotStuff将通信复杂度降低至线性，使其在大规模联盟链中更具可扩展性。
• PBFT与HotStuff均适用于企业区块链，因其在许可环境中可容忍恶意节点。
• PBFT与HotStuff的选择取决于容错性与系统效率之间的权衡。