As a Layer2, why zkSync ∎ Gas fee is high?

Haotian

23-04-21 14:41

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The original author: Haotian | CryptoInsight (twitter: @ tmel0211)

Maybe you're used to @arbitrum and @optimismFND charging around $0.70 for gas, so the interaction is smooth and unexciting. Recently, some people have been teasing @zksync that a $2- $5 gas bill is ridiculously high, not at all the low cost that L2 should be.

In the spirit of hardcore science, what is the difference between zk-rollup and op-rollup? And why zkSync Gas rates are currently higher.

When it comes to the ZK track, many people blurt out zero-knowledge proof, which is easy to attach to privacy features. But the mainstream discussion of zk-rollup is really about scaling performance, using SNARKs and STARKs to implement validaor proof. The existence of zero-knowledge privacy protection feature is weak in zk-rollup, so the concept of privacy is ignored and the technical principle behind it is considered from the perspective of "verifier proof".

In simple terms, all transactions in zk-rollup occur in the side chain,This is equivalent to using the zk technology algorithm to bundle these transactions into batches and generate SNARKs proof to be submitted to Mainnet. Mainnet smart contract will verify that all transactions in this batch comply with the rules through zk algorithmAnd then pack up the main chain. In this way, the transaction capacity and transaction speed of the main network are greatly expanded. Meanwhile, the intersection of the main chain reduces the gas consumption cost.

The logic of op-rollup is better understood. A large number of transactions are submitted to the side chain for calculation, packaging and accounting, and then the ledger results are aggregated into a block and synchronized to the mainnet smart contract.

In order to prevent the verifier from doing evil, fraud proof technology is adopted, that is, if the verifier submits a suspicious transaction within 7 days and it is confirmed, then the whole block will be rolled back, thus ensuring the security and integrity of the transaction.

zk-rollup and op-rollup are essentially different in validator proof and fraud proof.

The validator proof method is used to verify transactions. Although it consumes more computing power and resources, it can ensure the accuracy of the results within the block cycle, thus improving the transaction processing speed. op-rollup uses fraud proof, which saves resources but requires a waiting period.

Hard drill verifier proof and fraud proof techniques are too abstract, use an example to intuitively feel:

The screening of the novel coronavirus in the A community requires green code entry, so security guards are required to check in shifts, which is safe despite the high cost.

B community does not do any restrictions on people, but if people report that the community has a red code, immediately to all people blocked, until the risk is removed.

It is worth mentioning that op-rollup trades time for cheaper resources and consumption, but its side chain servers have some centralization risks, such as the sequence collator, etc. zk-rollup, on the other hand, uses short-term resource and computing power consumption to exchange for a shorter security confirmation time. Besides, account abstraction and distributed verification technologies avoid the risks of centralization.

So, zk-rollup gas is understandably expensive, there is no comparison.

Current transaction fees for zkSync depend on three things:

1) The cost of resources consumed by the verifier to generate SNARK proof and conduct verification, such as storage and calculation; These are higher fixed costs;

2) gas fee when the verifier submits the SNARK certificate to the Ethereum main network. The cost will increase as the main network becomes congested.

3) Service fees paid by the user to the verifier, including transaction confirmation, message broadcasting, etc.; The above expenses have to be covered.

In general, L2 user gas fee =zk system calculation and storage resource fee + main network gas fee per batch submission + verifier node incentive fee + others? . Main network gas and node incentive charges need not be mentioned.

Since the cost of computer resources is relatively fixed and will be diluted with more people, this means that gas rates will decrease with further mass adoption of zkSync. Yes, gas is now high not because of too much volume, but because there is not enough volume.

According toData from DuneAnalyticszkSync currently averages around 100,000 to 400,000 daily transactions. Although the mass of masturbators are still working hard, the zksync ecosystem is still an alpha baby compared to the ultimate goal of zk-rollup Star Ocean. How about we stop complaining about high gas and get on with building.