Community Controversy: Does sidechain count as L2?

This article summarizes the relevant controversies and discussions on Polygon sidechains and L2 in the community, and translates Dankrad Feist's article "About 51% Attacks, What Everyone Got Wrong" so that readers can refer to the answers to these controversies. On May 16, the market capitalization of Polygon, the Ethereum expansion solution, ranked among the top 20 in the market capitalization of cryptocurrencies. Then Uri Kolodny, the co-founder of StarkWare, retweeted his congratulations, but at the same time he emphasized: "Polygon is a side chain, not Layer-2. L2 The security of the side chain depends on Ethereum; and the security of the side chain is irrelevant (or even lower) to that of Ethereum.” Therefore, the community started a heated discussion around whether Polygon is L2 or not. In response to Uri Kolodny's comments, Mihailo Bjelic made the following reply: First of all, Polygon is not a side chain, it is a set of expansion solutions. Second (and most importantly), it is absolutely wrong to assume that L2 is more secure than a PoS sidechain (ours is the commit chain) by default. To explain why, I will briefly compare Polygon's PoS chain with StarkWare's zkRollup or Validium. Our PoS chain does have its own set of validators, but it's completely permissionless and has $2.8 billion staked. Additionally, the implementation has been battle-tested (14 million blocks with zero incidents). However, StarkWare Rollup has only one PoA operator. The operator may shut down, run away, review user transactions, etc. And, it's secured by STARKs, a brand new, unproven cryptography. As for Validium, the situation is even more worrisome. The Validium scheme used by DeversiFi also relies on a small set of PoA data availability nodes. These nodes can conspire to prevent any or all users from withdrawing funds by denying access to data. Considering the above, I think the idea that default L2s are more secure than sidechains/commitchains is wrong. In response to Mihailo Bjelic's reply, the community discussed from three perspectives: 1) the difference between Layer-2 and side chains in terms of security; 2) whether Layer-2 can achieve the same security as Layer-1; 3) The difference between Eth2 and side chains in terms of security. As for the confusion in the community, Dankrad Feist, a developer of the Ethereum Foundation, published the article "What everyone got wrong about 51% attacks" (see below), which basically included the questions and answers in the above discussions. The founder of YFI launched a new proposal in the Curve community to add cyDAI/cyUSDC/cyUSDT pool: According to official news, YFI founder Andre Cronje initiated the sCIP#28 proposal in the Curve community, suggesting to add a cyDAI/cyUSDC/cyUSDT pool. The proposal is not to add a gauge or a burner, just a transaction pool. The pool has already been developed and requires no additional man-hours from the Curve core team. More pools could provide deeper liquidity, better trades, and arbitrage between pools, the proposal said. [2021/1/27 13:37:21] 1. First of all, regarding the first question, Dankrad Feist disagreed. He said that L2 is indeed more secure, because as an L2, it must provide the same security as the base layer. Whereas PoS sidechains have the security of a weaker chain (usually a sidechain). James Prestwich also participated in the discussion: "Compared with side chains, L2 requires fewer new security assumptions, but its security is not exactly the same as that of the main network." He pointed out that L2 has the following different characteristics compared with side chains: Rely on non-censorship (fraud proofs) Rely on new cryptography and trusted settings (validity proofs) Add that Starks don’t need to rely on trusted settings Higher hardware and bandwidth requirements In the following, Dankrad Feist points out “side The chain does not verify the validity, only verifies most of the consensus conditions, and it does not have data availability checks." For the security issues of the side chain, see the "How does the side chain work?" part of the article. 2. As for whether L2 can achieve the same security as L1. Patrick McCorry believes that the goal of L2 is to be as close to the security of L1 as possible, but it is impossible to be exactly the same: fraud proofs are not a silver bullet, especially when the cost of issuing fraud proofs is too high, its security is Similarly, zero-knowledge proofs are not a panacea, and there will be situations where the sorter goes offline and L1 cannot cope with large-scale withdrawals ZB (ZB) official website announced that ZB (ZB) will start the thirteenth round of community voting for the coin from 14:00 on August 12th to 14:00 on the 14th: EJF vs TRAC vs DATA. EJF was qualified to list ZB (ZB) with 2,062,668 votes. According to official information, Enjoy Job Fee is a payment solution based on blockchain technology. EJF already has a large number of user groups at the beginning of its release, and has formed a mature user community through continuous preparation in the early stage. Coupled with the support of various applications such as online shopping platforms, game guessing, and wealth management products, EJF has a circulating application scenario at the beginning of its issuance. For more project details, please log in to the official website of ZB. [2020/8/14] He also mentioned that L2 solutions can be boiled down to the following four points: data availability (committee/rollup/etc) state transition integrity (zero-knowledge proof/fraud proof) withdrawal integrity (exit guarantee ) protocol liveness (choice of orderer) this mixed scheme is difficult to fully achieve L1 security. Back in the article below, Dankrad Feist explains "The Security Model of Blockchains" to highlight why L1 security is so difficult to achieve. 3. So how does Polygon’s PoS chain compare with Eth2’s PoS mechanism? During the discussion, Dankrad Feist pointed out that in the long run, the PoS side chain will be a big hidden danger. In Eth2 we try to remove most honesty assumptions, however PoS bridging cannot do that. The following is the content-zce of the article: Please forgive the provocative meaning in the title. Obviously, not everyone misunderstands 51% attacks, but there are still a fair number of people who don't, so writing an article about them wouldn't be a bad thing. ETC community statement: will investigate the crime of attacking ETC, and hold relevant responsibilities: In response to the recent reports about the situation encountered by ETC, the ETC community hereby declares: 1. This behavior is a criminal act, and the relevant personnel must bear the responsibility. 2. The ETC community will work with all righteous people to investigate this matter to the end. 3. The ETC Core team responded quickly and released parameters to ensure network security to ensure that similar attacks will not happen again. [2020/8/6] There is probably a myth in the blockchain circle: as long as someone controls more than 50% of the computing power of Bitcoin, Ethereum or other blockchains, then ta can do anything to the network. In the PoS (Proof of Stake) mechanism, as long as someone gathers 2/3 of the total pledge, ta can also do anything to the network. ta can transfer other people's assets, issue tokens at will, and so on. This thinking is wrong. Here's what a 51% attack can do: An attacker can prevent users from using the blockchain, i.e., intercept any transactions they don't like. This is called censorship. They can roll back the transactions of the blockchain, that is, undo a certain number of blocks and change the order of transactions in them. What they can't do: change the rules of the system. This means: they cannot simply issue new tokens outside the rules of the blockchain system; for example, Bitcoin currently has 6.25 BTC for each new block producer; they cannot turn this number into 1 million Bitcoins if They don't have the private key of a certain address, so they can't use the tokens of that address. The blocks they produce can't be larger than the consensus rules. This doesn't mean that the consequences of 51% attacks are not serious, which is still a very bad attack. Reordering transactions can cause double spending, which is a very serious problem. But there are still limits to what they can do. So most blockchains including Bitcoin and Ethereum, how do they ensure this now? What happens if a miner mines a block that violates the consensus rules? Or, what happens if a large majority of stakers sign a block that violates the consensus rules? Sometimes people claim that the longest chain is the valid Bitcoin or Ethereum chain. This statement is not complete. The correct definition of the current chain head is the effective chain with the highest total difficulty. HBTC Hobbit Exchange launched two community votes: According to the official announcement of HBTC Hobbit, in order to reflect the transparency, fairness and respect for the rights and interests of Hobbit captains, HBTC Hobbit Exchange was launched today after soliciting opinions from the Hobbit captain community There are two votes on "1000 Hobbit captain airdrop distribution ratio" and "About the transaction gift HBC unlock time". Every Hobbit captain can exercise his voting rights and participate in the decision-making of major events on the platform. HBTC Hobbit Exchange is a trading platform shared by 100% currency holders, and is jointly invested by 56 high-quality capitals such as Huobi and OKEx. With the upgrade of the platform token model, HBTC Hobbit has introduced two innovations: a brand new 10 times PE pricing repurchase model and Hobbit captain incentive model. Every Hobbit captain is a co-builder of the platform, and the Hobbit captain is currently recruiting, click the original text to view the details. [2020/5/19] Therefore, before clients accept the condition that the blockchain should be used to record current historical data, they need to verify two properties: the blockchain must be valid. This means, all state transitions are valid. For example, on Bitcoin, all transactions only spend transaction outputs that have not been spent before, coinbase only receives transaction fees and block rewards, and so on. It must be the most difficult chain. In layman's terms, this is the longest chain, but the "longest" is not measured by the number of blocks, but by how much mining power is spent on this chain. This might sound a bit abstract. We have reason to ask a question, who will verify the first condition above, that is, who will verify that all blocks on the blockchain should be valid? Because if the miners are still verifying that the chain is valid, then it's just duplication of work, and we don't really gain anything from it. But blockchain is different. Let's analyze why, starting with a common client/server database architecture: Note that with a typical database, users trust the database server. They don't check that the response is correct; the client makes sure it's validly formatted according to the protocol, that's all. The client (represented here by an empty square) is "dumb": it cannot verify anything. But in the structure of the blockchain, it is like this: Voice | Jiang Zhuoer updates the initial plan for BCH miner donations: I tend to start donating after the community reaches a basic consensus: Jiang Zhuoer just posted on Weibo to update the BCH miner donations Preliminary plan: 1. Start by computing power voting, if 2/3 computing power agrees, then start donation. 2. Miners donate 5% of the output, and miners can choose several donation targets: General Fund, ABC, BCHD, and ElectrionCash. 3. Donations last for 6 months (one version is only valid for 6 months). I recommend stopping the donation after 6 months and then turning it on again to prevent it from becoming a permanent rule. 4. There are still many objections at present, and I tend to start donating after the community reaches a basic consensus. If it cannot be achieved, you can build a general fund first, rely on donations to see the effect, and then conduct the next computing power vote. [2020/2/16] Let me first summarize the components included in the above picture. First miners (or stakers) produce the blockchain. A P2P (peer-to-peer) network ensures that everyone is able to use a valid chain despite the existence of some dishonest nodes (you need to be connected to at least one honest and well-connected P2P node to ensure that you are always in sync with the valid chain). Finally, the client sends the transaction to the P2P network and receives the latest chain update (or the full chain, if they are syncing) from other nodes in the network. Clients are actually part of the network and they will also contribute by forwarding blocks and transactions, but that's not so important here. The important part is that the user is running a full node, represented by the bars in the client in the diagram above. As soon as a client gets a new block, just like any other node, whether it's a miner or a node in a P2P network, these clients will verify that the block is a valid state transition. If this is not a valid state transition, the block is ignored. This is why it makes no sense for miners in the network to try to mine invalid state transitions. Everyone just ignores it. Many users run their own nodes, interacting with blockchains such as Ethereum or Bitcoin. Many communities have adopted this model as part of their culture, with a strong emphasis on everyone running their own node, whereby they become part of the validation process. Indeed, it is important to have the majority of users (especially those who have staked large amounts of assets) run full nodes; if the majority of users become lazy, then miners may suddenly be tempted to produce invalid blocks, thus This model will no longer apply. It's a bit like the separation of powers in a democracy - there are different branches of government, and just because you have a majority in one branch (like the legislature) doesn't mean you can do whatever you like and defy all law. Likewise, miners or stakers have the power to order transactions in the blockchain; they do not have the power to easily impose new rules on the community. But do all blockchains work like this? But do all blockchains work like this? That's a good question.

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Ethereum