As information processing modes continue to innovate and iterate, blockchain has gradually gained wide recognition because its decentralization and encryption characteristics have withstood the test of time. Blockchain technology has penetrated deep into every corner of the world and found increasing application in all sectors of society.

The Internet has evolved from the "Read Only" Web 1.0 and the "Read and Write" Web 2.0 to Web 3.0 in which individuals own information. Improved methods of information transmission also mean that the data is constantly protected by blockchain. The consensus mechanism is a core part of any blockchain technology and is at the center of blockchain network performance and security measures. Its settings determine whether a blockchain system can operate stably and efficiently over long periods of time. Prevalent consensus protocols include Proof of Work (PoW), Proof of Stake (PoS), and Delegated Proof of Stake (DPoS). There are also consensus mechanisms customized to meet the specific needs of different fields. Taking storage projects as an example, Filecoin's Proof of Replication (PoRep) + Proof of Spacetime (PoSt) mechanism and the latest Proof of Storage Service (PoSS) mechanism put forward by Datamall Coin (DMC) both have their advantages. Now, we will discuss various consensus mechanisms as below.

PoW is widely known because it has been adopted by Bitcoin. It is the consensus mechanism whose security performance has been verified for the longest period of time. PoW has the advantage of high degree of decentralization, but it requires a lot of computational power. Moreover, its efficiency is too low. That is why Ethereum has gone for the more efficient PoS. This mode distributes the corresponding interest according to the quantity and duration (i.e. coin age) of the coins held by users. However, the excessive centralization of coin possession widens the wealth gap between coin holders, which dampens the enthusiasm of retail investors.

EOS addresses above problem with DPoS, the principle of which is to elect n representatives through ballot by coin holders and turn these representatives into n super nodes with equal rights. Although the streamlined workflow increases efficiency, it nevertheless suffers the prominent disadvantage of centralization. It can be seen that no consensus mechanism is perfect, and there is unlimited room for improvement.

Now, let's turn our attention to two representative consensus mechanisms existing in storage projects. When we compare the differences between Filecoin and DMC, we actually explore what kinds of consensus mechanism they have found according to their specific needs.

Filecoin differs from other projects in that there are two kinds of proof: PoRep and PoSt, in the system. RoRep is an evolutionary version of Proof of Storage, which can prove that data has been stored by miners and ensure the independence of each data storage. After RoRep verification is completed, the PoRep algorithm will be repeated m times for computation, and the results obtained each time will be the input for a new round of PoRep computation. The final answer will be used as the result of PoSt. The Porep algorithm is used to resist three common attacks in decentralized systems: Sybil Attack, Outsourcing attacks and Generation attacks.

Filecoin stands as a special case since it concurrently adopts two mechanisms. Most projects only use one mechanism at a time. The latest Datamall Coin (DMC) storage project adopts a unique decentralized storage service network application consensus algorithm called Proof of Storage Service (PoSS), which takes the quantity of the staked Proof of Service Tokens (PSTs) cast by DMC as the voting right, screens miner nodes as the consensus nodes based on the voting right, and then provides storage service, namely mining.

Specifically, the PoSS consensus algorithm uses the quantity of the staked DMC-cast PSTs to proportionally generate the corresponding number of voting rights, and ranks the nodes accordingly to continuously select a certain number of miners who actively provide storage services as the consensus nodes and give them incentives according to the reward rules. PoSS provides a powerful safeguard mechanism to prevent Node hijacked attack and Collusion attack. The fair incentives under the consensus mechanism will eventually attract more miners who can provide storage services to join, thus injecting a continuous driving force for decentralized network storage service capabilities.

The PoSS consensus idea is geared to adapt to the storage development of future blockchain. However, only time and market tell which of the numerous consensus mechanisms at present will withstand the vigorous security performance test and stand out to become the next standard storage mechanism in the future.

References:

[1] KAUR, MANPREET. "MBCP: Performance Analysis of Large Scale Mainstream Blockchain Consensus Protocols."  IEEE Xplore, IEEE ACCESS Volume 9, 2021, 10 June 2021