In-depth Analysis of the Full Process of L2 Transactions and Security Analysis

L2 transactions have an important additional step compared to L1 transactions - waiting for the L2 block to be uploaded to L1. At this stage, users can only rely on the "Pre-Confirmation" provided by the Sequencer ( to determine whether the transaction has been included. This pre-confirmation is essentially just a verbal commitment from the Sequencer and may be violated due to malicious actions or bugs.

![Interpretation of the Full Process of L2 Trading: How is the Security Performance at Each Stage?])https://img-cdn.gateio.im/webp-social/moments-18277442c1e4f9f1ce90d4ac8fd99213.webp(

Currently, mainstream L2s display pre-confirmation statuses in their browsers, such as "Confirmed by Sequencer" for Arbitrum/Optimism or "Accepted on L2" for StarkNet. Users need to be aware that the confirmation guarantees provided by these statuses are only valid for the short term.

![Interpretation of the full process of L2 transactions: How is the security performance at each stage?])https://img-cdn.gateio.im/webp-social/moments-6886408298ee150407b06b75ce82f573.webp(

If you do not want to rely on the pre-confirmation of the Sequencer, you will need to wait longer until the L2 data is uploaded to L1 and receives sufficient confirmation. Different L2 explorers provide varying levels of support for this:

• Arbitrum shows L1 block confirmations
• Optimism directly shows L1 Finality status
• StarkNet only shows "Accepted on L1" status
• zkSync breaks down the L2 to L1 process into three stages: Committed, Proven, and Executed.

![Interpreting the full process of L2 transactions: how is the security performance at each stage?])https://img-cdn.gateio.im/webp-social/moments-03e7e7dbc69886b127390a01ed69cbab.webp(

To enhance the credibility of pre-confirmation, a smart contract mechanism can be introduced, requiring the Sequencer to stake a deposit and sign commitments. In the event of a breach, penalties can be enforced through the contract, providing users with clearer protection.

Overall, the security of L2 transactions improves progressively as the transaction process advances. Users need to weigh security against timeliness and choose the appropriate level of confirmation. In the future, with technological advancements, the transaction confirmation mechanism of L2 is expected to be further optimized.

![Interpretation of the full process of L2 trading: How is the security performance at each stage?])https://img-cdn.gateio.im/webp-social/moments-368473592dcd8248eb663a6a057e02fa.webp(