Bitcoin is to the left, Ethereum is to the right, which side do you stand on POW and POS?
Editor's Note: This article comes fromVernacular Blockchain (ID: hellobtc), reprinted by Odaily with authorization.
Editor's Note: This article comes from
Vernacular Blockchain (ID: hellobtc)
PoS VS PoW
, reprinted by Odaily with authorization.
Recently, Ethereum 2.0 released the news of the upgrade progress. Its founder Vitalik published an article detailing the three key reasons why Ethereum shifted from PoW to PoS, which aroused extensive discussions in the cryptocurrency community.
Therefore, Vernacular Blockchain invites Nervos Foundation co-founder & COO Lu Guoning, Cobo co-founder and CEO, F2Pool co-founder Shenyu Daniel, and Xinghuo Mining Pool product manager Miao Shu to talk about consensus mechanisms such as PoW and PoS .
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On November 4th, Vitalik Buterin issued a document saying that compared with PoW, PoS is a superior blockchain security mechanism. There are three reasons: PoS provides higher security at the same cost; PoS is easy to recover from attacks; PoS is more decentralized than ASICs.
PoW has two main advantages, but Vitalik Buterin believes that these advantages are quite limited: PoS is more like a "closed system", which will lead to a higher concentration of wealth in the long run; PoS requires "weak subjectivity", while PoW does not unnecessary. Do you agree with V God's views on PoW and PoS? What do you think about PoW and PoS?
Cobo&F2Pool Shenyu: The PoW consensus mechanism has been running stably for more than ten years, and has been verified by both theory and practice. Although new consensus mechanisms emerge in an endless stream, the status of PoW in the rivers and lakes remains undiminished.
At present, PoS also has a lot of flaws. It is mainly a kind of resource allocation in the system. PoW is more about using resources outside the system to obtain protection for the blockchain. These two co-governance methods have their own advantages and disadvantages. In the case of very strong security, PoW is more reliable.
Comparing the characteristics of the two, PoW is more suitable for fields that pursue absolute fairness and security, such as Bitcoin, various privacy currencies, etc.; in some fields that do not require high levels of decentralization but require higher performance, such as alliances Chain, PoS may be a better solution.
Uncle Xinghuo Mine: Vitalik described the advantages of PoS from his perspective. I think it’s pretty good, but I don’t fully agree with the conclusion that PoS is more secure. Some of them Factors need to be considered, such as openness, consensus scale, longer-term opportunities for fair participation, etc.
Vitalik himself actually said that PoW is more open than PoS, but he didn't say what was lost when PoW was transformed into PoS. I understand that an important part of this is missing is the people involved, or the complexity of the system game is lost.
The miner ecology in PoW is self-contained. They care more about practical factors such as electricity bills, machines, motherboards, power supplies, etc. Therefore, regardless of the activities on the chain, the core business logic of their participation in mining is established and can be traversed. Bulls and bears maintain the security on the chain, and PoS will abandon these people with a high probability, which brings more attention to the activities on the chain for maintaining network security, because they themselves mortgage the assets on the chain. I call it a phenomenon of consensus involution, that is, activities on the chain will directly affect the security of the chain itself for a long time, which is obviously not better than the current PoW consensus mechanism.
Let’s talk about the opportunity for long-term fair participation. The fairness achieved by PoW comes from the fact that the energy itself is sufficiently dispersed and diversified. No matter how the algorithm is updated, its core is the energy itself. The security on the chain is maintained by introducing external power (computing power); however, the closed nature of PoS will make participation an initial threshold. No matter how decentralized it is, it must not use energy such as electricity to complete long-term cost accounting and more directly. fair.
Nervos Lu Guoning: Of course I can’t agree with it, but I think it’s even more regrettable that what I see from this article is to abandon the objective and neutral perspective.
The analysis and comparison of the advantages and disadvantages of PoW and PoS seem to be evasive in this article, and even distort the facts. I prefer to understand that this article is at the end of 2020. Ethereum 2.0 will start Phase 0 immediately. The different voices from the community are whether to pursue the long-term uncertainty of Ethereum 2.0, or to be pragmatic after Ethereum 1.x. On the development of the Layer 2 solution, the community began to have more and more different voices. On the eve of the launch of Phase 0 of Ethereum 2.0, opening PoS and accepting user Staking, the effect of such an article is more to appease different opinions and encourage the community to actively participate in Staking.
If such an article is taken outside the Ethereum community to prove that PoS is superior to PoW, it is not surprising to see all kinds of serious developers and researchers on social networks, especially some who have deep research on the PoS mechanism. People raised a lot of doubts and disagreements with this article.
The debate on the pros and cons of PoS and PoW has been seen a lot since 2015, and there have been a lot of research and academic articles analyzing and comparing PoW and PoS from various angles over the years from the blockchain technology community to the academic circles, and Give professional analysis and suggestions for the problems that have been studied clearly, but whether it is the blockchain technology community or the academic circles, it has never been concluded that PoS is better than PoW, but divided into two camps. The camp continues to dig deeper and find more suitable scenarios to give full play to its advantages and avoid weaknesses. However, when I read this article, I did not see new research results or new evidence. What I saw were assertions and unrigorous conclusions.
1. PoS provides higher security at the same cost?
The calculation method of PoW attack cost in the article is almost completely unrealistic. The actual situation is that in the real world, only the GPU computing power rented through the NiceHash platform can launch attacks, but the GPU computing power has been well protected in the past five years. Is it contradictory to help the total asset scale of the Ethereum platform continue to grow, which has exceeded 100 billion US dollars?
Attacking by renting computing power through NiceHash (computing power leasing platform) is currently known as a way to launch a 51% attack on the network, and the total computing power that can be leased on NiceHash is limited, and the number of PoW networks that can be attacked is also very limited, and Using professional mining machines to launch 51% attacks is a problem of no practical significance.
Therefore, it is necessary to distinguish whether it is possible to launch a 51% attack by renting GPU computing power and whether PoW is safe. These are two different levels of issues. Being able to rent computing power through Nice Hash to launch attacks on small networks does not mean that PoW is not secure enough. 51% attack is a deterministic problem that can be prevented and solved through mechanism design and plan, while the uncertainty contained in the PoS mechanism has more problems that cannot be solved.
2. Regarding the efficiency of recovering from an attack?
The article points out an attack against PoW, but does not talk about the premise. The premise of this kind of attack is that the network PoW algorithm is based on GPU, and the basic computing power is weak. You can rent enough GPU through NiceHash to launch the attack. Only when all these conditions are met can you have the opportunity to attack. This attack method is harmful to ASIC The system is meaningless.
3. PoS is more decentralized than ASIC?
https://www.hellobtc.com/kp/mt/11/3005.html。
For the understanding of decentralization, at least three levels are scored, fairness, permissionless access mechanism, and anti-censorship. On these three levels, PoS cannot produce any evidence to prove that it is even as good as PoW, so in In the competition for the feature of decentralization, PoS does not compare with PoW, but chooses to compare with ASIC? However, ASIC does not harm fairness, permission-free access and anti-censorship. In contrast to PoS, the initial allocation problem cannot achieve real permission-free access and anti-censorship. These are the problems of the PoS mechanism itself.
The closedness of PoS leads to far greater problems than imagined, while PoW uses resources (energy) from the physical world to maintain the consensus of the network, and the distribution of resources in the physical world is naturally decentralized. Physical resources are Naturally decentralized, and the incentive mechanism urges participants to continuously search for and mine lower cost and more efficient resources. This competition mechanism further leads to the dispersion of resources rather than concentration. In contrast to PoS, if a monopoly wants to maintain its monopoly advantage, then the cost he pays must be lower than that of competitors, and the direct result of this mechanism is system involution (reaching the bottleneck, unable to make qualitative changes or quantitative changes).
Regarding weak subjectivity, it does not exist in the PoW system. Only in PoS, it is inevitable to rely on external information when judging the main branch. This problem is unsolvable in the PoS system, and it is also a problem that can cause far greater problems than imagined. In the early PoS research of Ethereum, the concept of "weak subjectivity" was created, but this concept has not really been recognized by the academic community until today. Some other deeper issues about PoS, which are discussed more clearly here:
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Will it eventually become a PoW chain of BTC?
Since the launch of Bitcoin in 2009, tens of thousands of blockchain projects have been born in the entire cryptocurrency world, and new consensus mechanisms have emerged in an endless stream. Some people believe that due to the 51% attack, in addition to Bitcoin, other token security aspects In fact, it is very bad. In the end, only one chain of Bitcoin will follow the road of PoW, and other public chains are only suitable for PoS or other consensus mechanisms. In the past, there have been repeated double-spending attacks on projects. What do you think of this problem?
Nervos Lu Guoning: It is very difficult to build a successful PoW chain, but the completed PoW is very safe. This is the characteristic of the PoW mechanism. Any project that chooses PoW as the underlying consensus mechanism must be very clear about this point. PoW The security of Bitcoin has been proved by 12 years of smooth operation of Bitcoin and 5 years of Ethereum, and today more than 80% of the assets in the entire blockchain field are still protected by PoW.
Some PoW chains with weak computing power and poor development are frequently exposed to rent computing power through the NiceHash platform to launch 51% attacks, but this does not mean that there is a problem with PoW. The development of PoW projects depends on design, execution, and implementation. Whether it is good or not determines whether this PoW chain can get out. In contrast to the PoS chain, let’s talk about recent events, such as NEO’s downtime problem and Tron’s downtime problem. In our opinion, there are many more problems caused by various PoS than PoW, so we can’t just because 51% The attack problem is that PoS is the solution, and PoS has its own problems as well.
Not all PoW chains are the same, and not all PoS chains are the same. When researching and discussing, we must look at mechanism design and how to balance and achieve goals objectively and neutrally. If you pay more attention to efficiency, such as alliance chains or industrial blockchains, If assets are to be protected securely and decentralized, then PoW is more suitable.
In 2020, the trend we see is that there are very few new PoW projects, and more new projects choose PoS by coincidence. This does not mean that PoS is better, but that it is easier to develop PoS in the early stage. To achieve the level of decentralization and security that is not inferior to PoW. To use an inappropriate analogy, starting a business is very difficult, and it is close to death. The vast majority of entrepreneurs have a small probability of success and a high probability of failure. Once successful, the growth and various benefits are very considerable, but it is easier to work, so starting a business The majority of them choose to work part-time, but you cannot say that part-time work is better than starting a business, the reason is the same.
Therefore, we understand the advantages of PoW, see that PoW is difficult, and should not give up on developing PoW. At least in Nervos, we have firmly chosen the path of PoW, and our PoW ecological development has far exceeded expectations. At present, we have passed After the 51% risk period, security concerns no longer exist.
Cobo&F2Pool Shenyu: In addition to Bitcoin, many new PoW projects have emerged in the past two years, and they are running well so far. I don’t agree with the saying that only Bitcoin will follow the PoW road in the end. Because the computing power is too concentrated or some currencies adopt the consensus algorithm used by other public chains, the attack cost is extremely low, and 51% attacks have indeed occurred on some small public chain projects.
The reason why double-spending attacks occur is that people do not pay enough attention to security, or they adopt the zero-confirmation method. Zero-confirmation is not safe at the network level, so don’t trust zero-confirmation.
Uncle Xinghuo Mining Pool: The scenario of the PoW chain being attacked by double spending has been proposed since Bitcoin, and the solution is the mechanism itself.
As long as the consensus is strong enough, a single chain can accommodate as much circulating computing power as possible for the corresponding mining algorithm, and it can resist 51% attacks from the outside. So the conclusion is obvious. In the end, there is not only one PoW public chain for Bitcoin, but each Hash algorithm field can have at least one PoW public chain with sufficient computing power. Ethereum is mainly used for GPU mining, so it can currently carry enough GPU computing power and maintain its security, which is enough to explain the problem.
Therefore, when choosing a consensus for a new public chain, you can choose PoS, which is no problem. If you choose PoW, you should consider making changes at the consensus algorithm level as much as possible to form an initial security barrier to prevent malicious computing power from easily attacking it. And complete the expansion process of the consensus, and give full play to the advantages that PoW should have.
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How will the consensus mechanism evolve in the future?
Because of its self-verification function, the blockchain complements the most important piece of the puzzle in the Internet world. It is precisely because of consensus mechanisms such as PoW and PoS that this function of the blockchain can be realized. From the perspective of cryptocurrency development, how do you think the future consensus mechanism will evolve?
Uncle Meow from Xinghuo Mining Pool: I think the pursuit of human beings has not changed since the beginning of civilization. We set up the Olympic spirit and pursue higher, faster and stronger. So as a consensus mechanism to ensure the security of the blockchain ledger, we are obviously making changes in this direction.
Nervos Lu Guoning: I think no matter how the consensus mechanism evolves in the future, the PoW mechanism will be an unsurpassable existence.
For blockchains, especially for decentralized blockchain systems that do not require permission, the primary task of the consensus mechanism is to ensure the security of the consensus. In other words, the most important product provided by the consensus nodes of the blockchain is security. The cost of generating security, whether it is electricity, ASIC equipment, or the capital invested behind it, is essentially through energy voting, and finally can be attributed to energy consumption, and energy consumption is a continuous physical process, so PoW The core is the proof of energy consumption, and the energy is "stored" in the form of tokens.
The security level of the system is directly proportional to the security investment, so how to measure it is a particularly important issue, and it is also the basis for everyone to build trust, especially the simpler and more intuitive way to verify the security investment, the better. On the premise that the security cost investment is simple and verifiable Under the circumstances, we can transform the judgment of the degree of safety into the judgment of the level of safety investment. From this point of view, energy input is the simplest, direct, pure, and easiest-to-measure method. Verifying PoW energy input can be as simple as a hash function verification with almost no cost.
