# L2 Interop Working Group - Call #14 **Sept 17, 2025** - [Recording](https://youtu.be/IuCnTL5aWpw) - [Calendar invite for future calls](https://docs.google.com/forms/d/e/1FAIpQLSfMFEJmyVgjLuiipgxprEkiQXwwK3F_PfGbWvU8ZmV6e_ka0A/viewform) ### [Agenda](https://github.com/ethereum/pm/issues/1725) 1. ENS-based chain registry, ERC-7828, ERC-7930, ERC-7785 (Unruggable + Wonderland) 1. Multiproving + [pragmatic fast finality](https://ethereum-magicians.org/t/a-simple-l2-security-and-finalization-roadmap/23309) 1. Permit3 (Eco) ## Call Notes *condensed notes below – watch the recording (above) for full discussion* --- ### Chain Registry and Identification Standards - ERC-7828 + ERC-7930 chain identification discussion - Unruggable team presenting registry contract and ENS-compliant resolver - Demo available: https://erc-7785-demo-ui.vercel.app - Convert between different chain identifiers (7785, 7930, coin types) - Wonderland team addressing ENS 32-byte limitations - Built custom resolver to handle longer identifiers - Repository: [https://github.com/defi-wonderland/L2Resolver](https://github.com/defi-wonderland/L2Resolver) - Resolver currently under internal security audit - Can extend to add properties like portal address, fraud proofs - Generalized chain identification concerns - Need unified approach beyond EVM chain IDs - Consider parachain IDs, Cosmos channels for non-EVM chains - Hash-based unified identifier instead of EVM-biased numbers - Questions about rollup address field for chains not posting to L1 ### Multi-Proving Initiative - Flashbots launching L2 multi-proving working group - Goal: make multi-proving default security model for L2s with significant TVL - Document: [https://hackmd.io/6BD6JVfbRKq2pIqJhJhOmQ](https://hackmd.io/6BD6JVfbRKq2pIqJhJhOmQ) - Learn more: [https://ethereum-magicians.org/t/a-simple-l2-security-and-finalization-roadmap/23309](https://ethereum-magicians.org/t/a-simple-l2-security-and-finalization-roadmap/23309) - Initial focus and approach - Target top 80% of TVL first - Research-engineering methodology with POCs - Keep logos/marketing out, focus on shared architecture - Start with OP Stack and Arbitrum Orbit multi-prover POCs - Technical considerations - Canonical rollup bridges as primary target - Parallel bridge approach for initial POCs - Design questions: optimal prover count, liveness properties, cost distribution ### Permit3 Cross-Chain Approvals - Eco team presenting Permit3 protocol - Enables cross-chain token approvals/transfers with single signature - Documentation: [https://eco.com/docs/getting-started/permit3/overview](https://eco.com/docs/getting-started/permit3/overview) - Repository: [https://github.com/eco/permit3](https://github.com/eco/permit3) - Technical architecture - Extension of Permit2 pattern to multi-chain setting - Creates Merkle tree from batches across multiple chains - Unbalanced tree optimization: Ethereum gets smallest proof (1 leaf) - Supports incremental allowances (increase/decrease vs set amounts) - Added NFT and ERC-1155 support beyond original implementations - Integration capabilities - Works with intent system through unique vault addresses - ERC-7702 upgrade path for infinite allowances - Smart wallet module available - Single signature can authorize multiple asset types across chains - Trust and security model - Emergency allowance lockdown system - No recourse for malicious spender (same as standard ERC-20) - Intent system provides action-specific vaults with refund mechanisms