[Advanced Mini-Class] What are the characteristics of Filecoin’s consensus mechanism?

The premise of this self-trust is the consensus mechanism of the blockchain, that is, in a market where there is no mutual trust, the necessary and sufficient condition for all nodes to reach a consensus is that each node, out of consideration for maximizing its own interests, will spontaneously and honestly abide by the rules pre-set in the protocol, judge the authenticity of each record, and finally record the records judged to be true in the blockchain. In other words, if each node has its own independent interests and competes with each other, it is almost impossible for these nodes to conspire to deceive you, and this is particularly evident when the nodes have public credibility in the network.

Blockchain technology uses a set of consensus-based mathematical algorithms to establish a "trust" network between machines, thereby creating new credit through technological endorsement rather than centralized credit institutions.

Consensus can be simply understood as the common understanding, values, ideas, etc. sought by different groups, and the unanimous agreement reached on a certain aspect. The consensus mechanism is to determine the way to reach a certain consensus and maintain consensus.

Today's blockchain consensus mechanisms can be divided into four categories: Proof of Work (PoW), Proof of Stake (PoS), Delegated Proof of Stake (DPoS) and Validation Pool (Pool).

1. Proof of Work (PoW):

PoW can be simply understood as a proof that you have done a certain amount of work. By looking at the results of your work, you can know that you have completed a specified amount of work. The most commonly used blockchain consensus algorithm is PoW. Both Bitcoin and Ethereum are based on the PoW consensus mechanism.

For example, Bitcoin uses the PoW mechanism in the process of generating blocks. Simply put, everyone competes for the right to keep accounts. Whoever gets it first and completes the accounting work correctly will get the system reward, which is Bitcoin, which is the so-called "mining". Miners complete this accounting work through the computing power of computers. This professional computer with computing power is the so-called "mining machine".

advantage:

① Complete decentralization, with free entry and exit of nodes, avoiding the cost of establishing and maintaining centralized credit institutions.

② As long as the computing power of the network destroyer does not exceed 50% of the total computing power of the entire network, the transaction status of the network can be consistent and the historical records cannot be tampered with.

③ The more computing power is invested, the greater the probability of obtaining accounting rights, and the more likely it is to generate new block rewards.

shortcoming:

① Currently, Bitcoin mining causes a large amount of computing power and energy waste.

② The mining incentive mechanism also leads to a high concentration of mining computing power

③ The settlement cycle is long, with a maximum of 7 transactions settled per second, which is not suitable for commercial applications.

2. Proof of Stake (POS):

The probability of getting bookkeeping is determined by the number and duration of holding tokens, which is similar to the dividend system of stocks. The more shares you hold, the more dividends you can get. Tokens are equivalent to the rights and interests of the blockchain system. Currently, many digital assets use POW to issue new coins.

advantage:

① Reduced resource waste of the PoW mechanism;

② It speeds up the calculation, which can also be understood as an upgraded version of proof of work;

shortcoming:

The longer the age of the currency, the greater the chance of the node obtaining the right to keep accounts, which is likely to lead to the Matthew effect, where the rich get richer, rights and interests will become more and more concentrated, and thus fairness will be lost.

3. Delegated Proof of Stake (DPoS):

It is a more professional solution derived from PoS, similar to board voting, where people with tokens vote for fixed nodes and elect several agents, who are responsible for verification and bookkeeping. Unlike PoW and PoS, where the entire network can participate in the bookkeeping competition, the bookkeeping nodes of DPoS are determined within a certain period of time. In order to encourage more people to participate in the election, the system will generate a small amount of tokens as rewards. BitShares adopts this method.

advantage:

Compared with PoW, DPoS greatly improves the ability of blockchain to process data, and can even achieve instant deposit, while also significantly reducing the cost of maintaining blockchain network security.

shortcoming:

The degree of decentralization is weak, the node agents are manually selected, the fairness is lower than PoS, and it relies on the issuance of tokens to maintain the stability of the agent nodes.

4. Verification Pool Consensus Mechanism (Pool)

This is a consensus mechanism based on traditional distributed consistency technology and data verification. It is currently widely used in the industry chain.

Advantages: Consensus verification can be achieved in seconds without relying on tokens;

Disadvantages: The degree of decentralization is weak, and it is more suitable for a multi-center business model with multiple parties involved;

Summary: Each consensus mechanism cannot meet the requirements of security, efficiency, and fairness at the same time. The weaker the degree of decentralization, the lower the security and the faster the blockchain; the stronger the degree of decentralization, the higher the security and the slower the blockchain. PoW is completely decentralized, but its operating efficiency is too low. PoS improves efficiency but reduces fairness and security. DPoS has a strong centralized characteristic but is the most efficient in the short term. Currently, the industry blockchain uses Pool consensus on a large scale.

• Sybil Attack: Using n identities, promising to store n copies of data D, but actually storing less than n copies (for example, 1 copy), but providing n storage proofs, the attack is successful.

• Outsourcing Attack: When the attacker miner receives a request from the verifier to provide proof of data D, the attacker miner generates a proof from other miners to prove that he has been storing data D, but in fact he has not stored it, and the attack is successful.

• Generation Attack: Attacker A can generate data D in some way. When the verifier verifies it, attacker A can regenerate data D to complete the storage proof, and the attack is successful.