# L2 Interop Working Group - Call #10
**June 25, 2025**
- [Recording](https://youtu.be/UojELYVU2eY)
- [Calendar invite for future calls](https://docs.google.com/forms/d/e/1FAIpQLSfMFEJmyVgjLuiipgxprEkiQXwwK3F_PfGbWvU8ZmV6e_ka0A/viewform)
### [Agenda](https://github.com/ethereum/pm/issues/1591)
1. Biconomy presentation: enabling gasless 1-click ethereum (Mislav)
- [slides](https://docs.google.com/presentation/d/1IZkXIgsSMC9Xe5fkUIMJS5xKQsUSZNI69OzttoJUMQI/edit?slide=id.p#slide=id.p)
3. [Kohaku](https://github.com/ethereum/wallet-poc) wallet: interop/acc + privacy prototype (EF + Wonderland)
4. Based rollups, shared sequencing, & how they fit into interop/acc
- Brecht (Taiko), Donnoh (L2BEAT), Drew (Fabric)
## Call Notes
*condensed notes below – watch the recording (above) for full discussion*
### TL;DR
- Enabling gasless, 1-click ethereum
- presentation from Biconomy to show how you can leverage "verifiable multichain scripts" to do complex, crosschain actions with one gasless click
- play with a demo at defi-demo.biconomy.io
- [Kohaku](https://github.com/ethereum/wallet-poc) wallet:
- prototype wallet focused on accelerating interop, crosschain UX, and privacy
- developed by teams from the EF and Wonderland (fork of Ambire wallet). Testnet-only.
- v1:
- interoperable addresses (7828 + 7930)
- crosschain sends using Open Intents Framework & Across 7683
- universal balances
- v2 coming soon w/ built-in 0xbow Privacy Pools
- Based rollups + shared sequencing
- overview of based rollups + interop benefits from Drew (github.com/eth-fabric)
- Brecht + Taiko on preconfirmations and their latest work
- Donnoh (L2BEAT) w/ his perspective and a call for more work on shared sequencing
---
## AI summary
### 1. Biconomy: Gasless One-Click Ethereum
**Presenter:** Mislav (VP Product, Biconomy)
**Links:**
- [Docs](https://docs.biconomy.io)
- [Blog Post](https://blog.biconomy.io/eip-7702-from-transactions-to-composable-multi-chain-programs-verfiable-scripting-on-the-evm/)
- [Slide Deck](https://docs.google.com/presentation/d/1IZkXIgsSMC9Xe5fkUIMJS5xKQsUSZNI69OzttoJUMQI/edit?slide=id.p#slide=id.p)
### Summary
- Introduced verifiable multichain scripts: calldata-encoded programs that execute on-chain across multiple chains.
- **Super Transactions**:
- Merkle root of function calls signed once by the user
- Enables multi-chain execution with a single signature
- **Gas Abstraction**:
- Cross-chain gas sponsorship (e.g. USDC on Arbitrum pays for gas on Base)
- **Orchestrator Accounts**:
- Scripts execute in isolated sandbox accounts using ERC-20 `approve` or EIP-7702/7715 delegation
### Key Features
- Composable batch calls with **dynamic parameter injection**
- Fully on-chain execution logic; relayers post calldata but don’t need trust
- Uses `abstract.js` TypeScript DSL for scripting (in development)
- Network is moving toward **permissionless relayers** with staking and slashing
### Demo Highlight
- User signed one transaction to:
- Transfer USDC from Arbitrum
- Supply ETH on Base to Morpho pool
- All without holding ETH or gas on either chain
---
## 2. [Kohaku](https://github.com/ethereum/wallet-poc) Wallet: Interop + Privacy Prototype
**Leads:** Ethereum Foundation + Wonderland
**Links:**
- [EF Notes](https://notes.ethereum.org/@rudolf/kohaku-wallet)
- [Wonderland Notion](https://defi-wonderland.notion.site/Interoperable-Addresses-Wallet-2019a4c092c780d09070fc06a1043303)
### Overview
- Prototype fork of **Ambire** wallet
- Experimental wallet for:
- Cross-chain UX (interop)
- Native privacy features
- Standards prototyping (ERCs 7683, 7828, 7930)
### v1 Features
- **Interoperable Addresses** (ERC-7828, 7930)
- Human-readable: `
[email protected]`
- Binary-encoded fallback
- **Cross-Chain Send** via [Open Intents Framework](https://github.com/ethereum/oif-spec) (ERC-7683)
- **Universal Balances**:
- e.g. aggregate ETH/USDC across chains into a single user-facing balance
- Future: support transfers/swaps using abstracted balances
### Privacy Roadmap
- Integrated [Privacy Pools](https://privacypools.com/)
- Key flows:
- Wallet-native “Private Mode”
- Compliance gate (delayed entry, vetting window)
- Session key support (EIP-7702)
### ENS + Chainlist Migration
- Moving GitHub-maintained chain metadata on-chain via ENS: `l2.eth`
- ENS DAO temperature check complete; waiting for controller upgrade to submit executable proposal
---
## 3. Based Rollups, Shared Sequencing, and Interop
**Speakers:** Drew (Fabric), Brecht (Taiko), Donnoh (L2BEAT)
**Link:** [eth-fabric composability guide](https://eth-fabric.github.io/website/education/composability)
### What are Based Rollups?
- Rollups that delegate sequencing to Ethereum validators
- Enable L1 ↔ L2 synchronous composability
- Bring L1-level censorship resistance and infra access to L2s
### Benefits
- Inherits L1 liquidity and tooling (e.g., Chainlink, USDC)
- Simplifies app deployment (one deploy → access from L1 + all based L2s)
- Improves decentralization and regulatory resilience
- Enables experimentation with custom sequencing rules
### Status & Infrastructure
- Live Based Rollups: Taiko, Facet
- Commit Boost: lets validators offer fast preconfirmations
- Signal Boost: rollups keep own sequencer but can request L1-based inclusion as needed
### Implementation Milestones
- Preconfirmations:
- Already live on [Taiko Hekla testnet](https://hekla.taiko.xyz/)
- Block confirmations every 2s with reduced cost
- Real-time proving progressing via ZKVM projects
- Preconfirmers moving from whitelisted → permissionless
### Challenges
- Real-time proving not yet available
- UX suffers from slow L1 slot time
- L1 cost (blob fees) remain high for frequent rollup publication
- Shared sequencing infra (e.g., Conduit, Superchain) still early
---