Ethereum’s Important Expansion Plan: Optimistic Rollup Status Report (Part 2)
This article is the third part of "Ethereum's Important Expansion Plan: Optimistic Rollup Status Report". Please refer to our previous articles for the first and second parts.
Block Production Block Production
Most projects adopt an open, permissionless block production model; that is, any party has the right to issue bonds and extend the ORU chain by proposing new blocks.
The only exception is IDEX 2.0, as IDEX has the sole permission to produce blocks. In this case, trustless properties can be maintained if the user is able to withdraw funds without the permission of the operator (i.e. withdrawing funds by directly issuing a transaction on the parent chain). Without this option, users would be helpless when encountering a malicious operator, as the operator would censor all withdrawal attempts by the user, effectively locking the user's funds on the rollup chain indefinitely. Likewise, in a permissioned system, it is not difficult for operators to gradually slow down block production or even stop production altogether; in this case, users would need to withdraw their funds.
IDEX 2.0 does provide users with an exit option from the main chain launch. One complication: these opt-outs must be verified/possibly reinstated in the event of fraud, and therefore must be accompanied by a guarantee against malicious damage. But considering that these exit options are supported, IDEX's permission model itself does not guarantee that the system is in a regulatory state (other permission-free chains also plan to adopt the main chain to launch the exit option in special cases).
Also most operations contain some insight into splitting block production into two steps: separate inputs for transaction inclusion and transaction ordering. These models address questions about censorship resistance and the chances of reducing front-running deals.
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Others, such as Optimism* and WCL, plan to use a proof-of-burn auction model for ordering transactions; after a set of transactions are covered, the transaction rights go to the party willing to burn the most Ether stake. The purpose of this is to reduce costs and open competition to minimize profit margins from parasitic first-mover opportunities and ideally reduce overall risk. Please refer to "Miner Extractable Value Auctions”。
The Fuel model has a block production cycle, within which there is a time window where a party (ie: a company/team) can obtain permission for sequencing rights. In this model, teams are in an advantageous position to capture value and monetize their applications without having to limit block production to what is allowed.
Finally, Celer's Rollup is unique in that block production itself contains its own independent consensus mechanism. Before developing rollup, Celer has planned to issue a certificate of Ethereum side chain rights (state guard network "State Guardian Network”) act as a watchtower for their national channel network. Participation in block production is not permitted and requires support for Celer’s token. Sidechains will use BFT consensus – such as Tendermint or similar. Celer plans to leverage this sidechain infrastructure to propose and publish ORU blocks (for more details, please refer tohere）。
trust assumption
Most projects strictly adhere to the trust requirements of the layer2 protocol described at the beginning of the article.
IDEX 2.0's reliance on data availability challenges makes this protocol a special case and outside the clearly defined scope of the ORU. When block producers propose a block, they initially only publish the Merkle root, with the implicit assumption that they will share relevant block data with off-chain validators. For example: if block data is never shared with a validator, the validator can issue a data availability challenge, forcing the block proposer to publish the data as call data (as was originally done in a typical ORU structure). If the block turns out to be valid, validators are penalized for invalid dispute challenges and have their stake slashed.
The problem at hand is: the disagreement outlined above is essentially arguing over which of the two parties actually owns the data;speaker/listener fault equivalence）,It is impossible to resolve such disputes objectively. Therefore, IDEX needs to be prevented from forcing malicious damage and ultimately punishing validators given concerns about reputation and incentives to continue participating and earning fees in the exchange ecosystem. Regardless of whether it is sufficient to prevent malicious behavior in practice, these assumptions are a security guarantee for ORU or Ethereum itself, so this challenge and penalty for data availability can be used as an additional trust assumption.
The only other project that (arguably) requires additional trust assumptions is ZK-ORU, which requires a trusted setup to create its snark circuits. Projects like ZCash and Aztec pass an elaborate ceremony (elaborate ceremony) to deal with this problem, as long as at least one of the n participants behaves honestly, it has encryption security; ANON plans to do something similar to ZK-ORU.
Finally, a number of projects, including Fuel, Optimism, and Nutberry, have discussed giving users the option of trust-based fast payments; a user, if they choose, could consider completing a payment before including it in a block. If the promise is broken, this fraudulent behavior will not be proven to the parent chain, but it can be proved to any third party. Crucially: this option is not mandatory and there is a noticeable difference in the UI; users who don't trust it at all can still choose to wait for block confirmations. Similarly, Celer plans to provide users with a series of security/trust parameters. Users can require all transactions to be announced immediately in the rollup block, or the sidechain that can accept the parameterized trust window before the chain is completed becomes smaller, And the mission criticality will be reduced.
profit
profit
All projects plan to release their work as free open source software.
ANON is planning to strictly release and implement it as a public welfare achievement, and there is currently no plan to directly capture value. PinkieBell (the only anonymous developer supporting Nutberry) also has no plans to monetize, but is currently considering a developer fee, a small fee from block producers to pay developers working on the project.
Five of these projects: Fuel Labs, Optimism, Interstate, WCL, and IDEX are planning to monetize their work in three ways: implementing examples of the projects, monetizing by charging transaction fees, and providing liquidity to users to withdraw funds quickly.
Although block production in Fuel, Optimism and Interstate is permission-free, if they (ie: companies) are the main block producers, everything is fine. They plan to make money by charging fees because they are in an advantageous position as a priority aggregator (discussed earlier).
At least one project has expressed uncertainty about the company's legal status as a payment processor and is awaiting further clarification on the issue.
Offchain Labs does not plan to list examples of Artibrum Rollup, but plans to use its own work to provide a corporate plan and support for the project, as well as some stronger guarantees in terms of economy and security to achieve profitability.
IDEX’s economic scheme is the most exhaustive; monetization is derived from a cryptoeconomic setup that includes exchange fees and the value inherent in the native token. Both block producers (IDEX) and validators are compensated, making IDEX also the only project attempting to directly incentivize validators. IDEX and Celer are the only projects planning to incorporate utility tokens. Several other teams scoffed at the notion of tokenization inherent in Layer 2 systems; others were more open to possible economic tokenization models, but felt more research was needed and there was no specific implementable plan.
User Experience / Validation
Most projects plan to support rollup on-chain transactions through metamask plugins. In addition to publishing their own front-end interfaces, the infrastructure tools for metamask plugins are basically ready.
All projects can function if not all users need to maintain uptime and validate all blocks; i.e., they expect two types of users: regular end users and power users (ie, validators). The essence of all ORUs is that as long as at least one honest party verifies and issues a proof of authenticity at any given time, all users are safe. The economic incentive method for verification is to directly issue rewards (only in the case of IDEX), and have the opportunity to produce blocks and collect fees, and have the opportunity to issue anti-counterfeiting certificates and receive rewards. Of course, the 22nd principle of anti-counterfeiting proof is that if the system design is reasonable, it is still hoped that fraud will not happen as much as possible (if it does happen).
Another direct incentive for verification is to trust the validator to quickly ensure that the transaction everyone cares about is completed; that is, without having to wait for the exit window to appear. The expected outcome is that the parties to benefit from this will be exchanges, wallet providers, liquidity providers with quick exit options, users capable of accepting large and significant transfers, high-end users/enthusiasts, and project creators. One team has suggested that miners could make it their job to validate the rollup chain, asking interesting questions about the interplay of incentives between layer 1 and layer 2 of the data used.
Open topics for research/discussion
BLS signature
Easily the hot topic of the moment; with BLS signatures, block producers can take a signature from each rollup block and replace them with a single aggregate signature, bringing on-chain data requirements closer to ZK- rollups. One of the more troublesome issues is that, if verified, verifying BLS signatures consumes more gas than typical ECDSA signatures. Barry Whitehat said: He has identified a feasible structure in preparation for the ORU focus area, but has not yet reached a consensus on the best signature aggregation scheme.
“Post-Data”
It is conceivable that if the use of rollup technology on Ethereum becomes the norm, what the future will look like when most of the chain data exists in the form of "rolling up"; that is, usable in terms of practicality, but not directly usable for implementation; This change could have significant economic and technical implications for Ethereum client implementations. One solution is to prepare for such a future by introducing a special field of transactional data, tentatively called "post-data", for usability only and without touching the state module or the EVM. With this in place, clients can process and store data more optimally, and ideally, gas prices will eventually decrease.EIPThere are broad outlines of this approach, but it is in its early stages.
Bond Size and Challenge Phase Parameters
Ideal parameters for bonds required for block production and time windows
Since most teams haven't settled on final numbers, it's still in the public discussion stage until blocks are finalized (and thus a pullback to the main chain is possible). A longer challenge period would better ensure that users have more time to detect fraud and better pressure miners trying to review proofs of authenticity. For some projects, it is best to be in a safe period of a few days to a week, because they will move closer to safety, and users will usually withdraw more quickly, either by atomic conversion to the chain or tokenization, or by Isn't it just to sell the exit option and use it as a bond (inPlasmastructure has already been discussed). Analysis by Ed Feltenanalysis, a shorter dispute window like 3 hours is sufficient.
planplanprivacy
privacy
One disadvantage of rollups relative to Plasma and channel structures is that they do not get the privacy benefit of data being completely off-chain; the only project mentioned here that provides the privacy benefit is ZK-ORU. Other projects are discussing creating privacy-focused rollups in two ways: implementing other well-known privacy techniques on the fabric (i.e., Tornado Cash - esque mixers or Aztrec-esque privacy layers) or creating hybrid rollup/federated data models such that Users can rely on a large amount of available data, thereby reducing the publication on the chain.
Block production model
Aside from the full EVM/application-specific split, one of the main debates between the teams seems to be which model of permission-free block production is acceptable and what the different models would yield, namely:
Does the single-priority aggregator model only incentivize more disruptive front-running when front-running decreases.
Will a wealthy party maliciously disrupt and effectively censor pure proof-of-stake - block production.
How the market value can be fully reflected and demonstrated in the proof-of-burn auction.
Some research and modeling may shed some light on these questions, but we may not be able to draw any conclusions until we see them put to the test in the wild.
Optimistic Game Semantics
Research by the Optimism team on the theoretical properties of layer 2 structures culminated in theOptimistic Game Semanticsin conclusion
in conclusion
Teams utilizing the Optimistic Rollup pattern draw conclusions from different perspectives: exploring the theoretical design space of different layer 2 structures, finding ways to efficiently run execution engines in the EVM, and trying to create more scalable versions of Ethereum's existing applications Etc. Converging to ORUs to get enough scalability benefits with minimal practical complexity is the best way forward.
We can only answer these open questions once we see these issues make it to mainnet, and see how the ecosystem chooses to use these tools; Something more realistic for practical use, plus some more specific benchmarks on gas cost and verification burden to give exact numbers in transactions. But with several projects already on the testnet, and no surreptitious research or usability challenges to be found, it's safe to assume we'll see practical applications soon. Scalable autonomous smart contracts are emerging.
*Correction: A previous version of this post indicated that Optimism's planned block production model allows them to be prioritized as locators; their MEV auction protocol does not actually privilege anyone. ThanksBen Jones。
Thank you to all the teams who participated in the interview, thank you for a very useful discussion.
Daniel GoldmanOriginal address:here。
Original address:https://medium.com/
