Optimism VS ZK, a list of Ethereum expansion technologies
Before launching the comparative analysis of Optimism Rollup and ZK Rollup,We need to understand the background of the birth of Rollup.
Rollup is considered to be the ultimate solution for the expansion of Ethereum. It executes transactions outside the first layer, but publishes transaction data on the first layer. This allows Rollup to scale the network and still gain security from Ethereum consensusfirst level title
Why do you need a Rollup expansion solution?
In fact, the research enthusiasm of Rollup is closely related to the development of Ethereum in recent years. Ethereum scaling has been one of the most discussed topics in the crypto space. Whether it is the CryptoKitties craze in 2017, the DeFi summer in 2020, or the cryptocurrency bull market in early 2021, the soaring demand for Ethereum has made the scaling debate heated up, and the soaring Gas fees have made the transaction fees paid by users more expensive.
At the same time, under the background of the rapid development of Web3,Ethereum increasingly hosts thousands of DApps. The huge transaction volume will inevitably bring about the limitation of operation speed, which makes the transaction speed of projects on Ethereum become slower and slower, and the retention rate of users also gradually declines.
Based on this, finding the perfect expansion solution has become an important goal for multiple teams and the entire Ethereum community. Generally speaking, there are 3 main ways to scale Ethereum:Expand the blockchain itself - Layer 1 (Layer 1) expansion; build on top of Layer 1 - Layer 2 (Layer 2) expansion and build side chains on the side of Layer 1.
Then the expansion principle of Rollup is to aggregate hundreds of processed transactions into a batch and execute the transaction on the L2 chain parallel to the Ethereum main network, and finally complete the transaction and release it to the bottom layer (L1, Layer 1) in batches Blockchain, in order to improve transaction speed and reduce Gas costs.
Among the Rollup solutions, Optimistic Rollup and ZK Rollup both perform well.In fact, the execution principles of Optimistic Rollup and ZK Rollup are similar, the difference lies in the verification method.first level title
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Optimism
Optimistic Rollup, as its name suggests, adopts an "optimistic" mechanism——Fraud proofs. The system defaults to the reliability of the transaction data, and it will directly enter the waiting period without valid verification. During the waiting period, if any node raises an objection and proves that it is a malicious transaction, the transaction will be canceled; if there is no objection, the transaction will be completed and written after the waiting period ends. into the block. The "fraud proof" transaction scheme eliminates the need for large-scale deployment verification, thereby saving computing resources and ensuring the accuracy of transactions.
In Optimistic Rollup, the prominent schemes are Arbitrum and Optimism. Although Optimism was the first to invent the Optimistic Rollup protocol compatible with EVM, Arbitrum gained a latecomer advantage due to the delay in the launch of the main network.
Optimism: Single-Round Non-Interactive Fraud Proofs
Optimism uses smart contracts to transfer transaction data from the Ethereum main chain to Layer 2. The sequencer can bundle multiple transactions into a batch, and then submit the batch back to the main through a single transaction. The sequencer executes the process optimistically under the assumption that all transactions are valid. The system sets a one-week waiting period, during which any challenge can be raised, and if there is an exception, a fraud certificate will be generated.
Arbitrum: Multi-Round Interactive Fraud Proofs
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ZK Rollup
ZK Rollup (Zero-Knowledge Proof), a concept introduced by MIT researchers in 1980, was once called "moon mathematics".
ZK Rollup is an expansion scheme through zero-knowledge validity proof. It batches off-chain transactions and generates cryptographic validity proofs to verify transaction authenticity.These proofs of validity add batches of transactions to the L1 blockchain that can be quickly verified by the L1 contract, while invalid batches are simply rejected.
If Optimistic rollups assume that everyone involved in a transaction is doing things out of good faith, ZK Rollups try to make sure that is the case. At present, the ZK Rollup layout mainly includes Hermez, ZKSync and so on.
Hermez: Generating concise non-interactive arguments of knowledge
Hermez can generate cryptographic proofs of SNARKs (Succinct Non-Interactive Proof of Knowledge), which has the ability to scale Ethereum to 2000 transactions per second. The system mainly relies on the coordinator to process and generate validity certificates. The coordinator is selected through an auction process, and the registered network nodes will bid to become the next coordinator. Currently, the Hermez team has announced that they are developing a Zero-Knowledge Ethereum Virtual Machine (ZKEMV), aiming for full opcode compatibility.
zkSync: Generating concise non-interactive arguments of knowledge
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Optimism VS ZK: Who is better?
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Development threshold and use cost
Optimism does not require large-scale deployment verification, and saves a lot of development steps on the premise that all transactions are valid, and publishes these verification information to the base layer. This is due to the fact that in an optimistic situation, without any additional work, it can greatly reduce the development threshold for technicians, saving a lot of time, energy, and money costs. If developers want to get started with Rollup solutions in a short period of time, Optimism is the first choice. Data shows that Optimism can provide up to 10-100 times scalability improvement.
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Smart contract enforceability
Optimism is highly interoperable and can also execute smart contracts. This allows Optimism to have more flexible operation space on L2, and the behavior of users to participate together makes Optimism's operation more "trustworthy", thus winning additional advantages such as better data protection and definite rights of both parties to the transaction. It's worth mentioning that most of the teams like Fuel, OMGX, Cartesi, etc. also tried to develop an EVM-compatible version of their Rollups, making Optimism more adaptable and performant.
However, ZK Rollup is currently mostly limited to simple transactions, which brings many limitations to the expansion of ZK Rollup. Therefore, at present, ZK can only support any smart contract written in Solidity through the compatible EMV virtual machine developed by ZKSync.Expand its application space. Or with Loopring, Hermez and ZKTubesecondary title
Execution efficiency of withdrawing funds
As a mechanism to guarantee user transactions and provide proof of ownership,The speed of withdrawal of funds after the transaction is also the key to the choice of developers and users. From this perspective, ZK Rollup has more advantages. Optimistim’s dispute resolution process is cumbersome, and all participants must be given sufficient time to submit proof of fraud before the transaction is finalized. This period is quite long, after all, to ensure the worst case, fraudulent transactions may still be appealed.It takes up to a week or two to withdraw funds from Optimistim.
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Strength of security and privacy protection
settlement "settlement", which is inherently different from Optimistim in validation. Like SNARK, STARK, PLONK and DARK, these proof strategies deployed on ZK Rollup include data footprint, proof time, verification time, collusion risk and other aspects of their respective security strength and risk proof.
It can be seen that compared with purely fraudulent proofs, ZK has set up multiple guarantees and verification mechanisms for security and privacy protection to ensure rigorous and thoughtful transaction verification.first level title
Optimism and ZK in 2023
As we can see, Optimism and ZK have their own advantages and disadvantages as Rollup solutions. In the new year, they will still innovate and iterate on their own paths,Perhaps we can expect that the two expansion solutions, Optimism and ZK, will be applied to more practical projects in 2023, and continue to empower the development of Ethereum.
For now, we can only conclude that Layer 2 will play an important role in making Ethereum more scalable, but which Rollup solution is better? There can be no definite statement. There is no doubt that Optmism and ZK will introduce more optimization measures towards becoming the "dark horse" in the direction of Rollup in the Web3 world.
In the long run, perhaps with the continuous development of ZK-related technologies, the limitations of ZK Rollup will be broken, bursting out a strong application potential. We also hope that in the future,These two Rollup solutions can achieve complementary advantages, integrate factors such as security and privacy, timeliness and cost, and development threshold into higher-quality products, opening up a new world.references:
references:
Optimistic, zk-Rollups, L3... Where has the scalability research of Ethereum come to now?
Ethereum’s Road to Scalability
Depth｜How to understand the prospects and differences between ZK and Optimistic Rollup?
Optimistic Rollups VS ZK Rollups: Six Most Exciting Ethereum Layer 2 Scaling Projects
The Future of Optimism: Bedrock Upgrade, Rollup Decentralization and Integration of ZK Solutions
