Multi-proof Design in the OP Stack

Recently, after the OP mainnet upgrade to Bedrock, an innovative feature was introduced - integrating multiple proof schemes into its design. This approach follows the concept of client diversity within the blockchain ecosystem, transforming the OP mainnet into a modular blockchain that supports a variety of proof schemes.

With the modular design of OP Stack and Bedrock, developers can quickly leverage various existing proof types while ensuring the system can adapt to future innovations. This unique feature not only has technological advantages but also has a profound impact on the entire ecosystem.

Challenges of Proof Schemes in Rollup Design

Traditional rollup design iterations primarily focus on creating a single proof and aligning the system with it. This approach limits the system’s flexibility and adaptability to evolving technologies. As a result, discussions in the L2 market mainly revolve around optimistic proofs and validity proofs.

In designing Bedrock, the development team is committed to changing this situation. They have made modularity a core design principle, building a system that can adapt to various types of proofs, providing developers with safer and more forward-looking proof solutions.

Advantages of Modular Design

Integrating multiple proofs into the OP Stack brings numerous benefits, with security being the most significant. Multiple proofs can prevent errors in a single proof from becoming a bottleneck for the system, similar to how L1 multi-client implementations provide better overall security.

This approach not only enhances technological decentralization but also promotes social decentralization. When multiple independent teams or stakeholders maintain different implementations, the interests of all parties are taken into account in the network roadmap.

The modular design of Bedrock has led to the emergence of multiple L2 client implementations in the Optimism ecosystem, which is a first in the L2 space. The extension of this concept allows the OP Stack to include multiple proofs, paving the way for adding zero-knowledge (ZK) validity proofs for the OP mainnet or other OP chains (such as Base), while ensuring compatibility with future technological developments.

Technical Implementation

The proof system in the OP Stack achieves modularity through standardized on-chain APIs and off-chain participants. This allows for flexible combinations of dispute contracts, making it easier to change proof schemes.

standardized on-chain API

Bedrock makes it possible to change proof schemes through standardized on-chain APIs, as long as the new scheme implements the standard API. This means that new proof schemes can be dynamically added, and it is even possible to create m-of-n schemes that require multiple proof schemes to operate the bridge.

Standardized Off-chain Participants

Off-chain participants or bots interact with dispute contracts. The system creates maximum extractable value (MEV) opportunities to incentivize honest behavior and protect the system, while adhering to the principle that participation in dispute games should always be profitable to ensure their continued operation. This model is establishing an open network of monitoring participants who can intervene to resolve disputes, thereby ensuring the security of the system.

Currently, the implementation of two standardized off-chain participants is under research.

Looking Ahead

The Bedrock upgrade and its support for multiple proofs align with the development team’s vision for a scalable network that does not compromise the ecosystem, applications, or collaborative capabilities. As the only L2 ecosystem designed for the simplicity of multiple clients and multiple proofs, Optimism is leading the industry towards a safer, more adaptable, more collaborative, and more optimistic future.