Layer 2: five separate questions

A layer-2 system can process activity away from Ethereum's base layer while relying on it for part of settlement or security. Implementations differ. Publishing a state commitment is not the same as publishing all the data needed to reconstruct that state.

Compare the components

Rollups: execution is only one part of the security model →

Ask where transaction data is available, how invalid claims are rejected, who orders transactions, who can change the contracts and how a user exits during an outage. A strong answer on one component does not settle the others.

For example, a functioning proof system may protect validity while a central sequencer delays inclusion. A bridge may require a waiting period even when the application presents an immediate confirmation. Administrative changes can alter assumptions after a review.

Check the current deployed configuration and the date of any risk assessment. A roadmap item is not an active protection. Arbitrum, Optimism and Base illustrate why chain-specific documentation matters.

来源

1. Ethereum: layer 2
2. Optimism: fault proofs

资料核对日期：2026年9月5日. Historical cases retain the date and legal status of the cited record.