Professional popular science
"consensus mechanism" is to complete the verification and confirmation of the transaction in a very short time through voting of special nodes; for a transaction, if several nodes with irrelevant interests can reach a consensus, we can It is believed that the whole network can reach a consensus on this. As a data structure that stores data in chronological order, the
blockchain can support different consensus mechanisms. The consensus mechanism is an important component of blockchain technology. The goal of the blockchain consensus mechanism is to enable all honest nodes to maintain a consistent view of the blockchain while satisfying the following two properties:
1) Consistency: The prefix part of the blockchain saved by all honest nodes is exactly the same.
2) Validity: the information published by an honest node will eventually be recorded in its own blockchain by all other honest nodes. The self-trust of
blockchain is mainly reflected in the fact that users distributed in the blockchain do not need to trust the other party of the transaction, nor do they need to trust a centralized organization, only need to trust the software system under the blockchain protocol to realize the transaction. The premise of this kind of self-trust is the consensus mechanism of the blockchain, that is, in a mutually distrusting market, the necessary and sufficient condition for each node to reach agreement is that each node will maximize its own interests. Spontaneously and honestly abide by the pre-set rules in the agreement, judge the authenticity of each record, and finally record the judged true record in the blockchain. In other words, if nodes have their own independent interests and compete with each other, it is almost impossible for these nodes to conspire to deceive you, and this is particularly evident when the nodes have a public reputation in the network. Blockchain technology uses a set of consensus-based mathematical algorithms to establish a "trust" network between machines, so as to create a new credit creation through technical endorsement rather than centralized credit institutions.
The consensus mechanism of current blockchain can be divided into four categories: workload certification mechanism, equity certification mechanism, share authorization certification mechanism, and Pool verification pool. Different consensus mechanisms are adopted on the
blockchain, which will have different impacts on the overall performance of the system while meeting consistency and effectiveness. Comprehensively consider the characteristics of each consensus mechanism, and evaluate the technical level of each consensus mechanism from the following four dimensions:
1) security. That is, whether it can prevent attacks such as secondary payment and selfish mining, and whether it has good fault tolerance. In the process of achieving consistency in a blockchain system driven by financial transactions, the main security issue is how to prevent and detect secondary payment behavior. Selfish mining is a theoretical attack method that threatens the security and fairness of the Bitcoin system by adopting appropriate strategies to release blocks generated by itself and obtain higher relative returns. In addition, Eclipse attacks control the network communication of the target object, forming network partitions and blocking the spread of transactions. Sybil attacks affect system security by producing a large number of meaningless nodes.
2) Scalability. That is, whether to support network node expansion. Scalability is one of the key factors to be considered in blockchain design. According to different objects, scalability is divided into two parts: the increase in the number of system members and the increase in the number of transactions to be confirmed. Scalability mainly considers when the number of system members and the number of transactions to be confirmed increases, the changes in system load and network traffic that will follow are usually measured by network throughput.
3) Performance efficiency. That is, the time delay from when a transaction reaches a consensus and is recorded in the blockchain to when it is finally confirmed can also be understood as the number of transactions that the system can process and confirm per second. Unlike traditional third-party supported trading platforms, blockchain technology reaches consensus through a consensus mechanism, so its performance efficiency has always been the focus of research. The Bitcoin system can process up to 7 transactions per second, which is far from supporting the existing business volume.
4) Resource consumption. That is, in the process of reaching a consensus, the amount of computing resources that the system will consume, including CPU, memory, etc. The consensus mechanism on the blockchain uses computing resources or network communication resources to reach consensus. Taking the Bitcoin system as an example, consensus based on the proof-of-work mechanism needs to consume a lot of computing resources for mining to provide proof of trust to complete the consensus.
Basic common sense
give a chestnut
We have 10 people to start a company, and we need to recommend a CEO from among them to lead everyone to work together. If everyone says what they say counts, the problem is who will listen to when everyone’s opinions are different of? In this way, a partnership will cause fatal management problems. Is it a recommendation?Who is the CEO? Is everyone willing to listen to his leadership? After everyone’s efforts, a consensus was reached, and the consensus mechanism produced a set of rules. Everyone voted together and finally selected a CEO from 10 people.
