Golden Depth丨Vitalik Buterin's own handwriting: "The Philosophy of Blockchain Verification" full text

Jinse Finance Blockchain News, August 19 Vitalik Buterin, the co-founder of Ethereum, published the paper "Philosophy of Blockchain Verification" on his personal website on August 17. Jinse Finance compiled this article as follows: A blockchain is the strongest One of the biggest features is that each part of the blockchain execution can be independently verified. Even if a majority of blockchain miners (or validators in a proof-of-stake blockchain) are taken over by an attacker, if that attacker tries to push invalid blocks, the network will simply reject those blocks. Even if users don't validate those blocks within a certain amount of time, they will potentially and automatically be warned, and can check if the attacker's blockchain is invalid and automatically reject those blocks before accepting a chain according to the rules . But how much validation do we really need? Do you need a hundred independent validators, or a thousand independent validators? Do we need a culture where every normal person in the world runs software to check every transaction? Solving the above problems will be a very important challenge if we want to build a blockchain with a consensus mechanism that is better than the original proof-of-work single-chain created by "Satoshi Nakamoto". Why does the blockchain need to be verified? The picture above shows a "51% attack" penetrating an invalid block, we want the network to reject this chain! Verifying the blockchain is very beneficial to users for two main reasons: 1. First, verifying the blockchain maximizes the chances that nodes can correctly determine to speak on the canonical chain (Golden Financial Note: The so-called canonical chain is the one recognized by the community. Blockchain) Typically, a canonical chain is defined as something like "the valid blockchain with the most miners/validators supporting that chain" (e.g., the "longest valid chain" in Bitcoin). Invalid chains are by definition rejected, and if a choice is made between multiple valid chains, the one with the most miner/validator support wins. So if you have a node that can verify all the validity conditions, thereby detecting which chains are valid and which are not, you maximize your chances of correctly detecting canonical chains. Jinse Finance Market Report | BTC short-term range continues to consolidate: According to the Huobi market, today BTC started to make a slight upward correction at noon after a slight correction in the morning, but the overall price is still in a high and narrow range between 11200-10900USDT, which did not continue the previous few days Daily bullish trend. From the daily chart, the bullish trend has weakened, but the overall trend is still in the bullish pattern. Looking at the 4-hour chart, Bollinger Bands show signs of upward divergence, the market is running on the middle and upper tracks, and the KDJ three lines gather upward. As of 18:30, the specific performance of mainstream currencies is as follows: [2020/7/31] 2. Secondly, there is a deeper reason for verifying the validity of the blockchain: suppose a powerful participant tries to push changes to the protocol ( Such as changing the token issuance), and with the support of the majority of miners, if no one else validates the blockchain, then this kind of attack is easy to succeed, because by default, everyone's client will accept the new chain, and wait until When people see what's going on, the dissenters will try to coordinate the rejection of that chain. However, if ordinary users are verifying, then the coordination problem falls on the other side: those who try to change the agreement will be responsible for convincing users to actively download software patches to accept the agreement. If enough users are validating, unnecessary confusion and disputes over forced changes to the protocol will be avoided. Chaos can cause a lot of damage, and it needs out-of-band social coordination to solve it. No motivation to attack. If the majority of users are validating (directly or indirectly) and the attack is only supported by the majority of miners, the attack will completely default to failure, which is the best of all outcomes. Definition Viewpoint vs. Coordination Viewpoint Note that this line of reasoning is quite different from another line of reasoning we often hear: "By definition", the chain that changes the rules is not actually the correct chain in some way, regardless of How many other users accept some new rules, the important thing is that you can still stay in the chain you like and follow the old rules. New product release conference | Jinse Finance will follow up to do 7*24 hours, uninterrupted opportunity warning: At 18:00 on April 2, Jinse Finance will hold a new product launch conference with the theme of "₿-ing", Chen Tianfu, Operation Director of Jinse Finance Firstly, the creation of the Golden Live Room is introduced. Then Chen Tianfu introduced the content-ethexc of the live broadcast room. In 2 weeks, we also invited 300+ big market Vs to settle in, and invited 200+ blockchain companies/founders to settle in. At the same time, we have also formed a team with 10+ years of experience in stock market live broadcast operations! Next, our products do only one thing: service. In addition to the well-known firm V and market V, we also mainly invited quantitative experts and index experts in the stock market and commodity futures market, such as Paul the Great, Bull and Bear Take-All, and Retail Investors for 20 Years, to settle in the live broadcast In the future, we will cooperate more closely to achieve 7*24 hours, uninterrupted opportunity warning. Truly achieve the perfect combination of man and machine, top trader + investment education dry goods, so that you can get both fish and fish. [2020/4/2] The diagram below is an example of Gavin Andresen's "by definition" perspective: Another perspective, from the Wasabi Wallet, is more interesting from the perspective of explaining why full nodes are valuable Direct: Note that there are two core parts to this argument: 1. By definition, the version of the chain that does not accept what you consider fundamental and non-transferable rules is not Bitcoin (or Ethereum or any other blockchain chain), regardless of How many others accept the chain. 2. The important thing is that you must keep the rules on the chain that you think are acceptable. However, I believe this "individualistic" view is very wrong. To see why, let's look at the situation we fear: the vast majority of participants may accept some change to the rules of the protocol that you would consider unacceptable. As an example, imagine we have a future where transaction fees are low, and almost everyone else agrees to change to a new set of rules that increase issuance in order to keep the blockchain secure, but you stubbornly keep running A node that continues to enforce the old rules and forks to a different chain than the majority of nodes. Jinse Finance mining data broadcast | ETH's network computing power rose by 3.11% today: Jinse Finance reported that according to the data from the spider mining pool: ETH's total network computing power is 175.993TH/s, mining difficulty is 2261.85T, and the current block height is 9731136. The theoretical income is 0.00811581/100MH/day. The computing power of the BTC network is 95.708EH/s, the mining difficulty is 16.55T, the current block height is 622711, and the theoretical income is 0.00001519/T/day. The BSV network computing power is 2.879EH/s, the mining difficulty is 0.39T, the current block height is 627543, and the theoretical income is 0.000627543/T/day. [2020/3/24] From your own perspective, you can still put tokens in a system that operates under the old rules that are acceptable. But so what? Other users won't accept your tokens at all, and exchanges won't accept your tokens either. The price website will list the price of the token, but their data source will definitely point to the token on the majority chain, so your token will be worthless. Cryptocurrencies and blockchains are fundamentally a social construct, and they mean nothing if no one else believes in them. So what is the alternative view? A core idea presented here is to view blockchain as engineering security through the coordination problem. In general, most of the coordination problems we encounter in our world are not good things, here are a few examples: 1. For most people, English is not actually "coordinated" because it is highly complex and has a lot of irregular Spelling system and phonological structure; 2. Some people think that the US might be better off if it switched to metric measurement; 3. Others feel that a 10% reduction in all prices and wages immediately in the event of a recession will help the country tide over , so in fact, everyone needs to agree to do so, and it is usually very difficult to achieve. Analysis | Golden internal reference: ETH breaks below $200 and a technical rebound is imminent: ETH fell by 12% in 24 hours, continuing to lead the decline of the top ten currencies in market value. Today, V God continues to spread from the "Hong Kong Ethereum Industry Development Summit" Speech, because of its disregard for the secondary market price, many people interpret it as negative, which leads to the loss of investor confidence, and the price hit a new low since August 2017. At present, it seems that there is not much positive support for the price from the fundamental point of view, but we When reviewing the historical trend, we found that the MACD divergence at the daily level is the first time we have paid close attention to this. Although the technical divergence cannot confirm that ETH has reached the bottom of value investment, the rebound after the divergence is formed is expected. After all After a relatively large and periodic decline, it is also necessary to correct the decline rate. Of course, V God cannot determine the price of the ETH secondary market, and we dare not jump to conclusions, so investors are requested to remain cautious and do a good job of risk control. For more golden internal reference content, click to view the "Original Link". [2018/9/9] However, in blockchain applications, we use coordination problems to our advantage, and use the friction created by coordination problems to resist the malfeasance of centralized enforcers. As another example, we can build a system with property X, and we can guarantee that the system always retains property X, but if we want to change the rule from X to not-X, we need a large number of people to agree to update their software at the same time. Even with an enforcer forcing the change, it would be very difficult - far more difficult than if a user were responsible for coordinating dissenters to resist the change. Note that this point of view has a special consequence: the core purpose of your full node is not just to protect you, and in the event of a contentious hard fork, people with full nodes are safer than those without full nodes. Humans are vulnerable. On the contrary, the point of view here is more of a point of view of group immunity, that is: the more people verify, the higher the security everyone has, even if only some people are verifying, the result will make everyone Individuals are afforded a higher degree of protection. Deep Dive into Blockchain Validation Now, we move on to the next topic, which is very relevant to topics like light clients and sharding: with validation, what are we going to accomplish? To understand this, let's go back to an earlier time - if there is an attack on the blockchain, the way the attack occurs may have the following order of priority: The company behind the project plans to add a banner to every page of the website explaining the November hard fork and its risks. [2017/10/9] The default is failure > The default is chaos > The default is victory The ">" here means "better than". The best is that the attack fails completely; the second best is that the attack causes confusion and everyone disagrees on the correct chain, and the worst is that the attack succeeds. The question here is: why is chaos so much better than victory? In fact, it is a matter of motivation, namely: confusion increases the attacker's cost, which means that the probability that the attacker will definitely win is greatly reduced, so the attacker is not encouraged to attack in the first place. The chaotic environment by default means that the attacker not only needs to win the blockchain war to conduct a 51% attack, but also convince the community to follow this "social war", which is much more difficult than just launching a 51% attack and winning by pure attack more, and much less attractive. The goal of validation is to go from the default state from victory to chaos (ideally) and from chaos to failure (less ideal). If you have a fully validating node, and the attacker tries to push a chain with a different rule, the attack will fail. If some people have fully validating nodes, but many others do not, the attack can lead to chaos. However, now we must think of another question, namely: Is there any other way to achieve the same effect? Light Clients and Fraud Proofs A natural development in this area is light clients with fraud proofs. Most blockchain light clients currently on the market work by simply verifying that a majority of miners support a particular block, without bothering to check that other protocol rules are enforced. That is, the client operates on the trust assumption that most miners are honest. In the event of a contentious fork, clients follow the majority chain by default, and it's up to users themselves to take active-ethexc steps if they wish to follow the old rules. Therefore, light clients under attack today win by default. But with fraud prevention technology, things start to look very different. The simplest form of fraud proof works like this: Typically, a single block in the blockchain only touches a small part of the "state" of the blockchain (such as account balances, smart contract code, etc...). If fully validated nodes process a block and find it to be invalid, they can generate a package containing the block—that is, a fraud proof—that will contain sufficient information to process the block. Blockchain state data for the block. The blockchain then broadcasts this packet to light clients, who can then receive the packet and use the relevant data to validate the block itself, even if they have no other data in the chain. As shown in the diagram above, individual blocks in the blockchain refer to only a few accounts. Fraud proofs will contain the data in these accounts along with a Merkle proof that this data is correct. This technique is sometimes referred to as stateless verification: a client can keep only the block headers instead of the full blockchain state database, and can verify any block in real time by asking other nodes for a Merkle proof of any desired state, In addition, the entries of the block verification can also be accessed. The power of this technique is that light clients only validate standalone blocks when they hear an alert (and alerts are verifiable, so if light clients hear false alerts, then they can just stop listening alerts for that node). So under normal circumstances, light clients are still light clients, they just check which blocks are supported by the majority of miners/validators.

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