[Paper Review] A Survey on Consensus Protocols in Blockchain for IoT Networks

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

Blockchain Technology Applications and Security46 references86 citations

TL;DR

The paper surveys blockchain-based consensus methods suitable for resource-constrained IoT devices, compares public and private/blockchain options, and outlines open challenges for IoT deployment.

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.

Motivation & Objective

• Evaluate how IoT constraints (limited computation, bandwidth, storage) affect blockchain consensus suitability.
• Survey and compare existing consensus methods for IoT applicability.
• Discuss private/consortium blockchain and tangle alternatives for IoT.
• Identify open research challenges and practical adaptations for IoT deployments.

Proposed method

• Provide an overview of blockchain fundamentals and consensus mechanisms.
• Analyze IoT network requirements and limitations to motivate adaptations.
• Review and categorize consensus methods (PoW, PoW alternatives, Byzantine agreement, and hybrids).
• Discuss private/consortium blockchain approaches (e.g., Hyperledger) and their suitability for IoT.
• Compare pros/cons of methods in the IoT context and outline adoption considerations.

Experimental results

Research questions

• RQ1 Which consensus protocols are feasible for resource-constrained IoT devices and networks?
• RQ2 How can blockchain be adapted (e.g., private blockchains, tangle) to meet IoT constraints without sacrificing essential guarantees?
• RQ3 What are the relative advantages and drawbacks of each consensus method for IoT deployments?
• RQ4 What open challenges must be addressed to enable widespread blockchain-based IoT implementations?

Key findings

• Proof of Work is impractical for IoT due to high computational and bandwidth requirements.
• PoC, PoET, and other low-power consensus variants offer energy efficiency, but come with trade-offs like storage or reliance on trusted components.
• Private blockchains (e.g., Hyperledger) reduce computation and latency but sacrifice some decentralization and openness.
• Byzantine fault-tolerance approaches (PBFT, dBFT, SCP, Ripple) offer high throughput and low latency suitable for smaller IoT networks, with scalability and network-overhead tradeoffs.
• Federated and Byzantine-based protocols can achieve low latency but may require trust assumptions or adaptations to IoT scenarios.
• The paper highlights open research challenges in scaling, security, privacy, and practical deployment for IoT-blockchain solutions.