Application of Multi-Proof Design in OP Stack

The security advantages of multi-client networks are well-known, but what if your favorite L2 could integrate multiple proof schemes into its design? This is exactly the situation after the OP mainnet upgrade to Bedrock.

Following the principle that client diversity benefits the blockchain ecosystem, OP Stack transforms the OP mainnet into a modular blockchain while supporting a variety of proof schemes. When using the modular design of OP Stack and Bedrock, developers can quickly leverage various existing proof types and ensure that the system can adapt to future proof innovations.

Let's delve into the technical aspects of this unique feature and discuss its broad impact on the ecosystem.

Challenges of Proof Schemes in Rollup Design

Previously, the iterations of rollup design primarily focused on creating a single proof and adapting the system to it. This approach limited the system's flexibility and adaptability to ever-changing technologies. Due to this design philosophy, the L2 market mainly revolves around debates on optimistic proofs and validity proofs.

When designing "Bedrock", we aimed to change this situation. We made modularization the core design principle of Bedrock upgrades, creating a system capable of adapting to various proof types, providing developers with safer and more forward-looking proof solutions.

Solution: Modular Design, Flexibility, and Security

The ability to integrate multiple proofs into the OP Stack brings numerous benefits, with security being the most significant. Having multiple proofs can prevent any single proof's error from becoming a fatal weakness. This is similar to how multiple implementations of an L1 client provide better overall security. Vitalik has written about how Ethereum's multi-client concept interacts with zk-evm. He noted that multi-client implementations are a form of technological decentralization, with the main advantage being the ability to resist errors within the network. If multiple independent teams or stakeholders maintain an implementation, it also leads to some form of social decentralization. The interests of each team are taken into account in the network's roadmap.

The modular design of Bedrock has already given rise to various L2 client implementations within the Optimism ecosystem, which is a first in the L2 space. We are expanding this concept to allow the OP Stack to include multiple proofs. This paves the way for adding zero-knowledge (ZK) validity proofs to the OP mainnet or other OP chains (such as Base), ensuring compatibility with future developments. The modular design of the OP Stack enables the easy adoption of new technologies in a secure and battle-tested manner without requiring significant changes to the codebase.

How It Works

The proof system in OP Stack achieves modularity through standardized on-chain APIs and off-chain participants. This allows for a mix-and-match of dispute contracts, facilitating the exchange of proof schemes.

standardized on-chain API

By standardizing the on-chain API, Bedrock makes proof exchange schemes possible as long as they implement the standardized API. This means that new proof schemes can be added dynamically, and we can even create an m-of-n scheme where multiple proof schemes are required to operate the bridge.

standardized off-chain participants

Off-chain participants or bots communicate with the dispute contract. The system creates Maximum Extractable Value (MEV) opportunities to incentivize honest behavior and protect the system, while adhering to the principle that participation in the dispute game should always be profitable to ensure its sustainability. Through this model, we are creating an open network of monitoring participants who can intervene to resolve disputes and ensure the security of the system.

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

The future belongs to the superchain

The Bedrock upgrade and its support for multiple proofs align with our vision for a scalable network that does not compromise the ecosystem, applications, or the ability to work collaboratively. As the only L2 ecosystem designed for the simplicity of multiple clients and multiple proofs, Optimism will lead the industry towards a safer, more adaptable, more collaborative, and more optimistic future.