Overview
Summary

The verification of Layer 2 state can be categorized into two types: fraud proof and validity proof. However, Morph proposes a new verification method called Responsive Validity Proof that combines the benefits of both methods.

The problem with fraud proofs is the wastage of capital efficiency and low security assumptions. Additionally, no OPRollup has implemented a permissionless fraudproof challenge mechanism. On the other hand, although validity proofs have high security assumptions and theoretical timeliness, practical operation faces cost and efficiency issues that impede the scalability of Rollups.

Morph combines Optimistic Rollup with Validity Proof and utilizes ZKProof to verify the correctness of the state. This approach is different from ZKRollups as the ZKproof is only generated when there is a state challenge. This method reduces the high cost of ZKproof generation and shortens withdrawal periods based on the nature of validity proofs.

By implementing ZKProof generation and verification, Morph can seamlessly switch to a complete ZKRollup in the future.