Modular Interoperability & The OP Stack - Mark Tyneway @Optimisim

Summary

Mark, a contributor to the Optimism Collective, discusses blockchain interoperability, focusing on the design philosophy of a modular interoperability stack. He highlights the importance of user experience, the architecture's flexibility, and the potential for shared sequencing and atomic composability. Mark also addresses challenges like centralization and the need for scalability in smart contract systems.

Takeaways

• 😀 The speaker, Mark, is a contributor to the Optimism Collective and discusses the concept of modular interoperability in the Optimism stack.
• 👋 Mark acknowledges the 'Sunny Army', a group of talented individuals active on Twitter, who are involved in the project.
• 🔗 Interoperability in blockchain allows different chains to read the state of others, with a focus on read-only interoperability in this talk.
• 🛠️ The design philosophy for building an interoperability stack should be minable, flexible, and compatible with existing tooling for developer adoption.
• 🏗️ The architecture should be generic to work with different rollup frameworks, though it's being developed specifically for the Optimism stack.
• 👤 The user experience is emphasized, highlighting the importance of designing features with the user in mind for better adoption.
• 🔑 Key properties of the design include the absence of forced inclusion of cross-chain messages, which simplifies the system and avoids complexity.
• 🔄 The design leverages out-of-consensus policy to scale, with block builders playing a role in the scaling process.
• 📝 The talk introduces the concept of 'initiating' and 'executing' messages for cross-chain transactions, and the importance of a dependency set of interoperable chains.
• 🛑 The system uses optimistic inclusion with fork-choice enforcement to maintain the integrity of cross-chain transactions.
• 🤔 The talk raises research questions about the limitations and potential of the design, such as the lack of replay protection and the implications for centralization.

Q & A

What is Mark's role in the Optimism Collective?

Mark is a contributor to the Optimism Collective, and he is discussing the topic of interoperability within the Optimism (op) stack.

What does the term 'interoperability' refer to in the context of blockchain?

In the context of blockchain, 'interoperability' refers to the ability of different blockchains to read the state of other chains, allowing for communication and interaction between them.

What is the significance of the 'Sunny Army' mentioned in the script?

The 'Sunny Army' is a term used to refer to the talented group of people who have contributed to the development of the interoperability stack, and they are gaining recognition on social media platforms like Twitter.

Why is it important for an interoperability stack to be minable and flexible?

An interoperability stack needs to be minable and flexible to ensure it can work with existing tooling and to encourage developer adoption, making it easier to integrate with various systems and adapt to different requirements.

What is the user experience design philosophy for creating cross-chain transactions?

The user experience design philosophy involves designing features from the user's perspective, ensuring that the process is simple and intuitive. In the case of cross-chain transactions, it involves sending a transaction to one chain that emits a log, and then submitting a transaction to another chain that includes a pointer to the log.

What are the two types of messages involved in cross-chain transactions?

The two types of messages involved in cross-chain transactions are the 'initiating message', which is the transaction on the source chain, and the 'executing message', which is the transaction on the destination chain.

What is a 'dependency set' in the context of interoperable chains?

A 'dependency set' refers to a group of interoperable chains that can all send cross-chain messages to each other, forming a network of interconnected blockchains.

Why is it important to avoid 'force inclusion' of cross-chain messages?

Avoiding 'force inclusion' of cross-chain messages simplifies the design and makes it easier to reason about, as it eliminates the need to consider the gas market on remote chains and the potential for denial of service attacks.

What is the role of block builders in scaling the interoperability stack?

Block builders play a crucial role in scaling the interoperability stack by helping to include cross-chain messages in their blocks. They can leverage out-of-consensus policies and perform static analysis to determine the validity of cross-chain transactions.

What is the concept of 'optimistic inclusion with fork choice enforcement'?

Optimistic inclusion with fork choice enforcement means that cross-chain messages are included in blocks optimistically, and the fork choice rule will reorganize (reorg) any blocks that contain invalid cross-chain messages, ensuring the integrity of the blockchain.

How does the design of the interoperability stack address the issue of replay protection?

The design addresses replay protection through the use of a higher-level abstraction called the 'Messenger', which provides replay protection and domain binding, ensuring that cross-chain messages can only be executed as intended on their target chains.

What is the potential impact of interoperability on the centralization of blockchain networks?

Interoperability can increase the hardware requirements for sequencers and full nodes, as they need to verify cross-chain messages, which could lead to centralization. However, the adoption of stateless execution schemes could mitigate this by reducing the need for full nodes to trust remote entities or perform their own executions.

What are the implications of the proposed interoperability stack for smart contract design?

The proposed interoperability stack suggests a need to rethink smart contract design to take advantage of horizontal scalability. This could involve designing smart contracts that can operate across multiple chains, potentially using abstractions like a distributed hash table that feels like regular EVM storage.

How does the script address the potential for atomic composability in cross-chain transactions?

The script suggests that atomic composability can be achieved without force inclusion, under the assumption of coordinated block builders. This allows for the creation of user experiences that are seamless and instantaneous, which is beneficial for applications like DeFi.

What is the significance of the 'eoa constraint' in the smart contract mentioned in the script?

The 'eoa constraint', which requires the message sender to equal the transaction origin, enforces that the cross-chain message is a top-level call frame. This is specifically for denial of service protection, making it easier for block builders to perform static analysis and ensuring the validity of cross-chain messages.

How does the script discuss the potential for shared sequencing in the interoperability stack?

The script suggests that the basic primitive for shared sequencing within the op stack is possible, allowing for block builders on different chains to coordinate and include cross-chain messages that reference each other, enabling more complex cross-chain interactions.