Interpretation of L2 Transaction Implementation Process: Security Performance Analysis at Each Stage

The process of L2 trading can be divided into the following key stages:

1. Users send transactions to the Sequencer
2. Sequencer packages transactions into L2 blocks
3. L2 block data uploaded to L1
4. L1 Block Confirmation
5. L1 block finally confirmed ( Finalized )

In this process, security is gradually improved:

• In the initial stage, there is only Pre-Confirmation from the Sequencer, with the lowest level of security.
• There is a slight improvement after the L2 block is packed, but it still relies on the Sequencer.
• The security significantly improves after data is uploaded to L1.
• After the confirmation of the L1 block, it can basically ensure the validity of the transaction.
• The L1 block achieves the highest security after being Finalized.

Different L2 projects have variations in the display of transaction status:

• Arbitrum/Optimism: Show "Confirmed by Sequencer" and L1 confirmation count
• StarkNet: There are statuses such as Received, Pending, Accepted on L2, and Accepted on L1.
• zkSync: Divided into three stages: Committed, Proven, Executed.

Overall, users need to weigh security and confirmation speed, choosing the appropriate confirmation stage based on their own needs. For large transactions, it is recommended to wait for L1 Finalized to obtain the highest security assurance.

Possible directions for future improvements include:

• Add economic incentive mechanisms for Pre-Confirmation
• Optimize the speed of L2 data upload to L1
• Provide richer trading status information

With the continuous development of L2 technology, the transaction confirmation process is expected to be further optimized, providing users with a better experience.