What Is The Blockchain Consensus Algorithm?

The essence of the blockchain system is distributed application software. The primary issue in distributed systems is how to solve the consistency problem, that is, how to reach consensus among multiple independent nodes.

In the presence of the possibility of faulty processes and network partitions, the FLP theorem completely closes the door to solutions under traditional computer algorithm systems. Inspired by sociology and game theory, we try to introduce the following mechanism.

(1) Incentive mechanism. For example, reward loyal generals in the Byzantine Generals Problem. We introduce the concept of game theory: we no longer divide nodes or generals into fair/malicious (loyal/betrayal) parties, and consider that the behavior of each node is determined by an incentive mechanism. We believe that there is no distinction between good and evil in human nature from the beginning. Sexual good and evil are determined by incentives behind the scenes. If the incentive mechanism is properly set up, considering that each node has the tendency to maximize its own interests, most nodes will abide by the rules and become fair nodes.

(2) Randomness. In the Byzantine Generals Problem, deciding the next move requires the generals to coordinate and determine a unified next step plan. In a traditional centralized system, decisions are made by authoritative generals. In a decentralized system, what rules are used to determine who has accounting rights?

1) Determined based on the computing power (power) of each node (universal). Whoever has stronger computing power and solves a certain difficult problem can obtain accounting rights (command rights in the Byzantine Generals Problem). This is a PoW consensus protocol.

2) Determined based on the resources (equities) owned by each node (general). The resources used cannot be monopolized. Whoever invests more resources will get the accounting rights. This is a PoS consensus protocol.

For the above considerations, we introduce two consensus algorithms to try to better solve the Byzantine Generals Problem. Distributed consensus protocols have the following two properties:

1. If all fair nodes reach a consensus, the consensus process terminates;

2. The final consensus must be fair.

Different aspects of the consortium chain involve centralization and decentralization at different points. Peer-to-peer networks are the closest thing to a decentralized system. Anyone can run a consortium chain node, and there are basically no barriers to entry. But the trend towards concentration in the mining sector and the concentration of mining capabilities is very high.

The assumption of fair node selection can achieve "implicit consensus". Our consensus protocol has multiple rounds, each corresponding to a block in the blockchain. In each round, a random node is selected that can propose the next block of the chain. Consortium chain consensus algorithm, the simplifying assumption of this algorithm is that a node can be selected at will, and these nodes will not be affected by the Witch attack.

1. New transactions are broadcast to all nodes.

2. Each node puts the new transaction into the block.

3. In each round, a random node can broadcast its block.

4. Other nodes can choose to accept this block, provided that the transactions in the block are legal (have real signatures).

Nodes can put the hash value of the above block into their own block to show their approval of this new block.

For the smooth operation of the alliance chain, the public must reach consensus on the following three issues:

1. Consensus on rules. The rules mentioned here include the mechanism to ensure that transactions or blocks are valid, as well as the core protocols and data formats involved in runtime. People need to agree on these rules so that all participants in the consortium chain system can communicate with each other and agree on what is happening.

2. Consensus of historical records. Participants must agree on the content of the blockchain, including what does and does not belong on the blockchain, so that the public can agree on how to confirm transactions that have occurred. On this basis, the public can reach consensus on the amount of unspent output and its owners. This consensus arises from the process of creating a blockchain and getting individual nodes to agree on their understanding of the contents of the blockchain. This is the most commonly used and technically complex consensus in the alliance chain.

3. Alliance chain value consensus. The third consensus requires that the public generally believes that the alliance chain is valuable. The basis for the existence of any currency, whether it is a fiat currency like the US dollar or a digital cryptocurrency like Bitcoin, is valuable. consensus. There is a general public belief that it can be traded and redeemed for other things of value now or in the future.

This third consensus has a certain circularity. That is, I believe that the alliance chain I receive today is valuable, and it depends on the people I hope to receive the alliance chain tomorrow also believe in its value. Therefore, the basis of value consensus lies in the consensus of value continuity. This is sometimes called the "fairy effect" ( ), a name taken from the fairy tale Peter Pan, in which the fairy exists because you believe she exists.

Author: Hong Kong International New Economic Research Institute; from ChainDD open content platform "DeDeHao". This article represents the author's views only and does not represent an official position. All "Dehao" articles must be original and authentic. The contributor guarantees that if the manuscript is plagiarized, tampered with, etc. and causes legal consequences, the contributor himself will be responsible for the publication of the article on the Dehao platform. If there is any infringement, violation of regulations or other inappropriate speech content, readers are kindly requested to supervise it. Once confirmed, the platform will be taken offline immediately. If you have any questions about the article content, please send them to:

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