# L2 Interop Working Group - Call #19 **Feb 11, 2025** - [Recording](https://www.youtube.com/watch?v=olS6ShxQA4Q) - [Calendar invite for future calls](https://docs.google.com/forms/d/e/1FAIpQLSfMFEJmyVgjLuiipgxprEkiQXwwK3F_PfGbWvU8ZmV6e_ka0A/viewform) ### [Agenda](https://github.com/ethereum/pm/issues/1899) 1. Onchain registry for chain IDs and on.eth resolver [Unruggable] 1. Using EIP-7702 + 5792 to execute multi-step, cross-chain actions [Effortless/Palis] 1. Open Intents Framework - roadmap and updates [Orca] 1. Sync composability - Jordi's [ethresearch post](https://ethresear.ch/t/synchronous-composability-between-rollups-via-realtime-proving/23998) - Nethermind fast composability for based rollups (related to [same slot composability](https://ethresear.ch/t/same-slot-l1-l2-message-passing/21186)) ## Call Notes ### Onchain Registry for Chain IDs using on.eth Resolver [Unruggable] - Chain resolver code complete and finalized - Executable proposal to register on.eth name and set resolver ready within 24 hours - 7-day timeline with complete ENS community support expected - Experimental registry resolver live on Mainnet at CID.eth - Testing completed, issues fixed, ready for production - User interface available at [https://cid.eth.limo](https://cid.eth.limo) - Registry architecture supports aliases (OP and Optimism point to same metadata) - Multisig allocation process in development - Industry participants from EF and ENS - Chain ownership will transfer to appropriate chain operators - Wonderland team created [https://interopaddress.com](https://interopaddress.com) with SDK experimental support - SDK flag enables integration with experimental registry - Production registry support available in ~7 days - Positive feedback from L2 event in Malaysia - ZK Sync said “just ship” with strong support - Short coordination window for maximum impact **Key Links:** - [https://github.com/unruggable-labs/chain-resolver](https://github.com/unruggable-labs/chain-resolver) - [https://discuss.ens.domains/t/executable-register-on-eth-to-the-ens-dao-wallet-and-set-the-resolver/21894](https://discuss.ens.domains/t/executable-register-on-eth-to-the-ens-dao-wallet-and-set-the-resolver/21894) - [https://eips.ethereum.org/EIPS/eip-7930](https://eips.ethereum.org/EIPS/eip-7930) - [https://ethereum-magicians.org/t/erc-7828-chain-specific-addresses-using-ens/21930](https://ethereum-magicians.org/t/erc-7828-chain-specific-addresses-using-ens/21930) ### EIP-7702 + 5792 for Multi-Step Cross-Chain Actions [Effortless/Palis] - Goal: Self-custody UX competing with centralized solutions - Single-click approvals for complex multi-step actions - Bridge to L2 + swap + staking/lending in one transaction - Architecture combines EIP-7702 and EIP-5792 with dedicated L2 for record-keeping - L2 purely for transaction confirmation tracking across chains - Solvers optimize transaction parts, intents handle others - User experience: Express intent in layman terms to AI agent - AI creates complex transaction requiring single signature - Complete self-custody maintained (no fund transfers to third parties) - Open standard approach - not competitive with existing L2s/wallets - Value-add for ecosystem applications and wallet integration ### Open Intents Framework Updates [Orca/Wonderland] - Full-stack framework for intent-based cross-chain interoperability - Collective work from OpenZeppelin, [LI.FI](http://LI.FI), Uniswap, and EF - Open source public good avoiding vendor lock-in - ERC-7683 interface evolution - Moving from standardized events to on-chain resolvers - Resolver-based pattern supports more protocols than event-based approach - OIF contracts audited and production-ready - Modular smart contracts for intent settlement - Settlers and oracles manage intent fulfillment verification - Broadcaster implementation (ERC-7888) - Storage proof-based messaging between chains with common ancestors - Trust-minimized oracle option for rollup-to-rollup connectivity - Currently being audited by OpenZeppelin - OIF specs standardize user-solver interfaces - Quote requests, intent submission, asset discovery - Moved from binary 7930 addresses to human-readable text identifiers at API level - Reference solver available on Arbitrum, Base, OP with mock USDC tokens - Interop SDK with cross-chain module implementing OIF specs - Documentation and demos releasing imminently ### Synchronous Composability Research - **Jordi’s Approach: Proxy-Based Cross-Rollup Calls** - Separates data from proofs for cross-rollup composability - Proxy addresses enable L1-to-L2 and L2-to-L1 calls without contract redeployment - Execution lookup tables pre-populated by sequencers - Real-time proving enables <2 second latency - Current: 7 seconds average with 16 GPUs - Target: <2 seconds with pipelined block generation and proving - Proving cost marginal compared to transaction fees - Demo showed synchronous L1-L2 counter increment - **Nethermind’s Same-Slot L1-L2 Messaging** - L1-to-L2 synchronous composability using Taiko stack - Cross-chain DEX demo: ETH on L1 swapped using L2 liquidity, USDC returned to L1 - Architecture uses “hot state” - single EVM storage slot state - Builder sequences: L2 call transaction, L2 block proposal, L1 call transaction - Hot state hash stored in anchor transaction (first transaction in block) - Permissionless process - users can manually sequence if builder fails - No major modifications to default Taiko bridge - plugin-based approach