A Review of Blockchain Consensus Mechanisms:

Abstract

Abstract: Blockchain is an emerging digital technology for creating decentralized systems which disrupts the digital world with its complex and robust architecture. It has a range of application domains; from cryptocurrencies to decentralized software applications which are commonly known as DApps. The consensus mechanism is the core of Blockchain technology. Reaching a common agreement among the nodes of a decentralized distributed network is a vital but challenging process in consensus mechanisms. Consensus mechanism enables adding a new block to the blockchain making it transparent, trustworthy and immutable. This paper presents a systematic review of existing mainstream consensus mechanisms to highlight their strengths, impulsions and limitations, and the evolution of consensus mechanisms. On the basis of their canonical properties, each consensus mechanism is having its own performance characteristics. The performance of a consensus mechanism is determined in various criteria such as throughput, mining power, energy consumption, fault tolerance, and more. However, there is no fixed common scale yet to measure the performance. At present a particular consensus mechanism is adopted by an application domain purely based on subjective criteria including trial and error. Therefore selecting the most appropriate consensus mechanism in a particular application domain requires a systematic set of guidelines to be developed. By exploring the existing literature on various consensus mechanisms and their performance characteristics, this paper facilitates the researchers to identify the most appropriate consensus mechanism for a given application domain.