Analysis of Ethereum Layer 2 Solutions

Ethereum, as one of the most active blockchain platforms today, hosts a large number of decentralized applications, and its ecosystem is very prosperous. However, this has led to issues such as network congestion, soaring transaction fees, and extended confirmation times, which severely affect user experience. To address these challenges, the community has proposed Layer 2 (L2) scaling solutions.

The core idea of Layer 2 is to transfer computation and transactions from the mainnet (Layer 1) to the second layer network for execution, only submitting the final results to the mainnet. This approach not only improves efficiency and reduces costs but also maintains the security of the mainnet. Currently, the mainstream Layer 2 solutions include Rollups and sidechains, with Rollups further divided into Optimistic Rollups (OP-Rollups) and Zero-Knowledge Rollups (ZK-Rollups).

Optimistic Rollups

OP-Rollups adopt an "optimistic" strategy, assuming all transactions are valid. It performs transaction computation and state updates on the L2 network, and then batches the compressed raw data for submission to the mainnet. This approach significantly improves transaction speed and reduces costs.

After the transaction is submitted, there is a seven-day dispute period. If a problem is found, the validator can submit a fraud proof. Once malicious transactions are confirmed, the relevant batches and subsequent batches will be rolled back, and the malicious nodes will be punished. The existence of this mechanism itself serves as a strong deterrent, and in practice, very few nodes attempt to act maliciously.

However, OP-Rollups also face some challenges, such as a seven-day challenge period that may affect fund liquidity, and potential centralization risks.

Zero-Knowledge Rollups

Compared to OP-Rollups, ZK-Rollups require an additional validity proof when submitting data. This method conducts transactions off-chain, but a validity proof must be calculated before submission.

Although ZK technology has existed for a long time, it has found new application scenarios in the blockchain field. It confines complexity within smart contracts and only requires verification of data and computations on the blockchain, without relying on centralized organizations or individuals.

The complexity of ZK-Rollups lies in the need to compile complex logical circuit diagrams based on the data and logic of transaction execution, and then generate quickly verifiable results through cryptographic calculations. This process typically requires specialized compilers and verifiers.

Cost of Layer 2

The costs of OP-Rollups mainly come from two aspects: the transaction fees for submitting compressed data to L1 and the operating costs of L2 nodes. Recently, Ethereum's EIP-4844 proposal has significantly reduced the costs of interactions between L2 and the mainnet. Furthermore, node maintenance requires locking a large amount of funds, which may lead to opportunity costs.

The main cost of ZK-Rollups comes from computational resources, as generating zero-knowledge proofs requires significant computational power and specialized hardware. At the same time, it also needs to bear the transaction fees for submitting data to the main chain. The demand for specialized hardware may lead to greater centralization of the network.

Summary

Whether it's OP-Rollups or ZK-Rollups, both are important solutions for the Ethereum ecosystem to address scalability challenges. As Ethereum continues to upgrade, especially with the implementation of EIP-4844, the data publishing costs for L2 have been significantly reduced, which will further unleash the potential of both solutions and promote the continuous development of the Ethereum ecosystem.