[论文解读] A Survey on Consensus Protocols in Blockchain for IoT Networks

Mehrdad Salimitari, Mainak Chatterjee|arXiv (Cornell University)|Sep 14, 2018

Blockchain Technology Applications and Security参考文献 46被引用 86

一句话总结

本文综述适用于资源受限的物联网设备的基于区块链的共识方法，比较公共和私有/区块链选项，并概述物联网部署的若干未解决挑战。

ABSTRACT

The success of blockchain as the underlying technology for cryptocurrencies has opened up possibilities for its use in other application domains as well. The main advantages of blockchain for its potential use in other domains are its inherent security mechanisms and immunity to different attacks. A blockchain relies on a consensus method for agreeing on any new data. Most of the consensus methods which are currently used for the blockchain of different cryptocurrencies require high computational power and thus are not apt for resource-constrained systems. In this article, we discuss and survey the various blockchain based consensus methods that are applicable to resource constrained IoT devices and networks. A typical IoT network consists of several devices which have limited computational and communications capabilities. Most often, these devices cannot perform intensive computations and are starved for bandwidth. Therefore, we discuss the possible measures that can be taken to reduce the computational power and convergence time for the underlying consensus methods. We also talk about some of the alternatives to the public blockchain like private blockchain and tangle, along with their potential adoption for IoT networks. Furthermore, we review the existing consensus methods that have been implemented and explore the possibility of utilizing them to realize a blockchain based IoT network. Some of the open research challenges are also put forward.

研究动机与目标

• 评估物联网的约束（有限的计算、带宽和存储）如何影响区块链共识的适用性。
• 调查并比较现有的适用于物 IoT 的共识方法。
• 讨论面向物联网的私有/联盟区块链和 Tangle 等替代方案。
• 确定面向物联网部署的未解决研究挑战及实际改进方案。

提出的方法

• 提供区块链基础与共识机制的概述。
• 分析物联网网络的需求与限制，以便促发相应的改进。
• 回顾并对共识方法进行分类（PoW、PoW 替代、拜占庭式一致性，以及混合模式）。
• 讨论私有/联盟区块链方法（如 Hyperledger）及其对物联网的适用性。
• 在物联网情境下比较各方法的优缺点，并概述采用时的考虑事项。

实验结果

研究问题

• RQ1 哪些共识协议适用于资源受限的物联网设备与网络？
• RQ2 如何进行区块链的适配（如私有区块链、Tangle）以满足物联网的约束，同时不牺牲基本保障？
• RQ3 各共识方法在物联网部署中的相对优点与缺点是什么？
• RQ4 需要解决哪些开放挑战以实现广泛的区块链物联网部署？

主要发现

• 工作量证明由于高计算和带宽需求而对物联网不切实际。
• PoC、PoET 以及其他低功耗共识变体提供能源效率，但也带来存储或对可信组件依赖等权衡。
• 私有区块链（如 Hyperledger）可降低计算和延迟，但在去中心化和开放性方面有所牺牲。
• 拜占庭容错方法（PBFT、dBFT、SCP、Ripple）提供高吞吐量和低延迟，适合较小的物联网网络，但存在可扩展性与网络开销的权衡。
• 联合/拜占庭基础的协议可以实现低延迟，但可能需要信任假设或对物联网场景的改造。
• 本文强调了在物联网区块链方案的扩展性、安全性、隐私和实际部署方面的若干开放研究挑战。