# L2 Interop Working Group - Call #4 **Feb 24, 2025** - [Recording](https://youtu.be/pb76xwgXkSI) - [Calendar invite for future calls](https://docs.google.com/forms/d/e/1FAIpQLSfMFEJmyVgjLuiipgxprEkiQXwwK3F_PfGbWvU8ZmV6e_ka0A/viewform) ### [Agenda](https://github.com/ethereum/pm/issues/1320) 1. Review of the Open Intents Framework 2. L2 interop [GitHub Repo](https://github.com/ethereum/L2-interop) 3. [Intents w/ atomic swaps](https://github.com/ethereum/L2-interop/pull/16) [demo from Layerswap] 4. [Aztec's RFP](https://forum.aztec.network/t/request-for-grant-proposals-cross-chain-bridges-up-to-us-150-000/7477) for cross chain interop 5. [Broadcaster ERC](https://github.com/ethereum/ERCs/pull/897) [Arbitrum] - [reference implementation](https://github.com/OffchainLabs/broadcast-erc/tree/main/contracts/reference-impl) - [presentation](https://docs.google.com/presentation/d/1vHn5HKYo6stPZ7NiiJJBKzv8ggynGbw-dD38ksEg_iw/edit#slide=id.g30dd9367804_0_5) ## Call Notes *condensed notes below – recommend watching the recording (above) for full discussion* ### **Intro** - "Solving interop" = there is no meaningful difference to most users between using a single chain and using all chains across Ethereum. - In the near-term, a simpler goal: users can easily and quickly move the most common assets across all Ethereum chains. - How? We need "fast bridging". Intents are a great way to get fast bridging, and it's a solution we know works today on Ethereum. - To get fast/secure bridging in all the places where users need them, it helps if there is a common standard/framework (for ease of deployment and compatibility). - This common standard should be modular and should support all settlement systems. This is the goal of the Open Intents Framework (but still much work to do). ### TL;DR - Started off the call with feedback/questions on the Open Intents Framework (openintents.xyz) - Some discussion around risks of moving too quickly / whether it is stable enough today. Agreed we should take time to incorporate feedback to ensure we are building on the right foundation (e.g. how do different flavors of resource locks best fit in) and avoid any sort of vendor lock-in. - Also need time to make sure we have clear, shared understanding of the goals and "success criteria" for the OIF over the next 3-6 months (thx to Philipp/LIFI, VC/Socket, and others for their feedback here!) - Agreed to do a separate breakout call focused on the OIF to properly go through feedback / make sure we continue to accelerate in the right direction. - While we continue working on OIF, we are also pushing forward with other necessary ingredients for interop such as chain-specific addresses (ERC-7828) and on-chain configs (ERC-7785). - We will soon begin work on an experimental wallet (proof-of-concept) to incorporate all of these interop ingredients in one place and let users play with an end-to-end interop experience. - Took some time to review our new L2-interop github repo, as a central place to organize technical discussion. Open call for anyone who wants to help maintain the repo, as we are already getting lots of PRs/issues :) - Aram from Layerswap gave a quick demo of their work on atomic swaps with local verification (see their recent work on Train - protocol for trustless bridging) - Rahul from Aztec shared their recent RFP for privacy-preserving cross-chain apps/bridges (up tp $50k available per team, DM @iamRahul20 on TG) - Henry from Offchain gave a walkthrough of their new crosschain broadcaster ERC (number tbd), to enable trustless message passing across L2s/L3s. --- --- AI Summary (may contain some inaccuracies) --- ### Open Intents Framework (OIF) Discussion - Framework aims to make intents modular and unopinionated for adoption by L2s, wallets, dapps, and accesible to all users of Ethereum - Three main components: - Open source solver implementation - Modular smart contracts for execution/settlement - Customizable UI template - Key feedback - Support for intents everywhere - agreed this is needed - EIP-7683 standardization - supported but possibly too early for specific implementation - Risk of building on immature standard - creating technical debt - Need clearer differentiation between required vs optional components in OIF - Discussion about missing RFC phase and need for more structured feedback ### Layerswap Demo - Demonstrated trustless bridging solution between networks - Key features: - Completely trustless protocol - Permissionless network joining (only requires HTLC contract deployment) - Uses Helios light client for transaction verification - Demo showed transfer from Arbitrum to Optimism using two-step confirmation process ### Aztec Cross-Chain RFP - Aims to bring privacy features to existing L2s - Key capabilities: - ZK proof of passport for DeFi interactions - Private multisig control across chains - Privacy pools and rate limiting - Viewing keys for regulatory compliance - Supports both private and public execution with atomic communication between domains - Testing deployment planned for current quarter ### Cross-Chain Broadcaster Standard - Presented by Offchain Labs team - Enables trustless cross-rollup message passing using storage proofs - Components: - Broadcaster contract: stores messages - Receiver contract: processes storage proofs - Blockhash prover contracts: verify block hashes across chains - Handles heterogeneous rollup stacks through unified API - Discussion about potential extension as light client standard ### Next Steps and Action Items - Schedule dedicated follow-up discussion on OIF feedback - Need to address cross-chain token standardization - Continue async discussions in Telegram group - Focus on solving token vendor lock-in issues identified by Socket and others as top priority