Development in Consensus Protocols: From PoW to PoS to DPoS

Consensus protocols are the essential algorithms to achieve overall network reliability in the distributed system. As the representative of the distributed system, the blockchain applies its specific consensus algorithm to ensure security and consistency in the system. The three main consensus algorithms in the blockchain system now are Proof of Work (PoW), Proof of Stake (PoS), and Delegated Proof of Stake (DPoS). The development process of consensus algorithms illustrates the trend of consensus protocols in the blockchain. This paper analyzes the development of three representative consensus protocols: PoW, PoS, and DPoS. Then we compare the advantages and disadvantages of them and discusses the future direction of consensus protocols.