The End of Ethereum Islands: How EIL Reconstructs Fragmented L2 into a "Supercomputer"?

Author: imToken

In the previous article of the Interop series, we introduced the Open Intents Framework (OIF), which acts like a universal language that allows users to express their intent, such as "I want to buy an NFT across chains," and be understood by solvers across the network (further reading: “When 'Intent' Becomes the Standard: How OIF Ends Cross-Chain Fragmentation and Returns Web3 to User Intuition?”).

However, merely being "understood" is not enough; it must also be "executed." After all, once your intent is expressed, how do funds safely move from Base to Arbitrum? How does the target chain verify that your signature is valid? Who pays for the Gas on the target chain?

This involves the core of the "Acceleration" phase in the Ethereum interoperability roadmap—the Ethereum Interoperability Layer (EIL). Recently, at Devconnect, the Ethereum Foundation's account abstraction team officially brought EIL to the forefront.

In simple terms, EIL has an ambitious goal: to make the user experience of all L2s "feel like it's on the same chain" without hard forks or changes to Ethereum's underlying consensus.

1. What Exactly is EIL?

To understand EIL, it is essential not to be misled by the term "Layer," as EIL is neither a new blockchain nor a traditional cross-chain bridge.

It is essentially a set of standards and frameworks that combines "account abstraction (ERC-4337)" with "cross-chain messaging" capabilities to create a virtual unified execution environment.

In the current Ethereum ecosystem, each L2 is an isolated island. For example, your account (EOA) on Optimism and your account on Arbitrum, while having the same address, have completely isolated states:

• A signature on chain A cannot be directly verified by chain B.
• Assets on chain A are invisible to chain B.

EIL aims to break this isolation through the following two core components:

• Smart Accounts Based on ERC-4337: Utilizing the capabilities of account abstraction to decouple user account logic from keys; solving the problem of lacking Gas on the target chain through a Paymaster mechanism; and achieving multi-chain state synchronization through Key Manager.
• Trust-Minimized Messaging Layer: Establishing a standard that allows UserOps to be packaged and securely transmitted to another chain via the official Rollup bridge or light client proofs.

To illustrate, previous cross-chain interactions were like traveling abroad, where you needed to exchange currency (cross-chain assets), obtain a visa (re-authorization), and follow local traffic rules (buying target chain Gas). In the EIL era, cross-chain interactions will resemble using a Visa card:

No matter which country you are in, as long as you swipe your card (sign), the underlying banking network (EIL) will automatically handle the exchange rate, settlement, and verification, making you unaware of any borders.

The EIL proposal put forth by the Ethereum Foundation's account abstraction team envisions a future where users can complete cross-chain transactions with a single signature, without relying on centralized relayers or introducing new trust assumptions, allowing for seamless settlements between different L2s directly from their wallets.

This is closer to the ultimate form of "account abstraction." Compared to the current high-threshold and fragmented operations, this experience will help users automatically create accounts, manage private keys, and handle complex cross-chain transactions.

Especially with the native account abstraction feature (AA), all accounts can become smart accounts, allowing users to focus on on-chain experiences and asset management without worrying about Gas fees (or even being unaware of their existence).

2. The Paradigm Shift from "Cross-Chain" to "Chain Abstraction"

If EIL is successfully implemented, it could very well bridge the "last mile" for the widespread adoption of Web3. This marks a shift in the Ethereum ecosystem from multi-chain competition to chain abstraction integration, potentially solving the most troublesome issues for users and developers.

First, for users, it enables a true "single-chain experience."

In short, under the EIL framework, users no longer need to manually switch networks. For example, if all your funds are on Base but you want to play a game on Arbitrum, you can simply click start in the game, and your wallet will pop up a signature box. Once you sign, the game begins.

In the background, EIL will automatically package your UserOp from Base and transmit it to Arbitrum via the messaging layer, with the Paymaster covering the Gas and entry fees, making it feel as smooth as playing the game on Base.

Secondly, from a security perspective, it completely eliminates the single-point risk of multi-signature bridges.

Traditional cross-chain bridges often rely on a group of external validators (multi-signatures). If this group is compromised by hackers, billions of dollars in assets are at risk. EIL emphasizes "trust minimization," leaning towards utilizing the security of L2 itself (such as Storage Proofs) to verify cross-chain messages rather than relying on external third-party trust. This means that as long as the Ethereum mainnet is secure, cross-chain interactions are relatively safe.

Lastly, for developers, there will be a unified account standard. Currently, if a DApp wants to create a multi-chain application, developers must maintain several sets of logic. With EIL, developers can assume that users have a full-chain account and only need to write interfaces based on the ERC-4337 standard, naturally supporting full-chain users without worrying about where user funds are located.

However, to realize this vision, we face a significant engineering challenge: how to allow the existing hundreds of millions of EOA users to enjoy this experience? (further reading: “From EOA to Account Abstraction: Will the Next Leap in Web3 Happen in the 'Account System'?”)

After all, migrating from EOA to AA requires users to transfer their assets to a new address, which is cumbersome. This leads to the EIP-7702 proposal previously put forth by Vitalik Buterin, which cleverly resolves the compatibility issues that have been contentious among the previous three proposals (EIP-4337, EIP-3074, EIP-5003) and does something remarkable: it allows existing EOA accounts to "temporarily transform" into smart contract accounts during transactions.

This proposal means you do not need to register a new wallet or transfer assets from your current wallet like imToken to a new AA account address. Instead, through EIP-7702, your old account can temporarily gain smart contract functionalities (such as batch authorization, Gas payment, and cross-chain atomic operations), and after the transaction, it reverts back to being a highly compatible EOA.

3. The Implementation and Future of EIL

In fact, compared to OIF, which is co-built by the community in a "bottom-up" manner, EIL carries a stronger official tone, being a project led by the EF account abstraction team (the creators of ERC-4337).

Specifically, the current progress is mainly reflected in the advancement of the following three key dimensions:

• Multi-Chain Expansion of ERC-4337: The community is researching how to expand the UserOp structure of ERC-4337 to include cross-chain information such as target chain IDs, which is the first step in giving smart accounts "far-sight."
• Collaboration with ERC-7702: With the advancement of EIP-7702 (which gives EOA smart account capabilities), ordinary EOA users will also be able to seamlessly connect to the EIL network in the future, significantly lowering the user threshold.
• Standardized Messaging Interfaces: Similar to the intent standardization discussed in the previous article about OIF, EIL is promoting the standardization of underlying message transmission. Optimism's Superchain, Polygon's AggLayer, and ZKsync's Elastic Chain are all exploring interoperability within their respective ecosystems, while EIL aims to further connect these heterogeneous ecosystems to build a universally applicable messaging layer.

Interestingly, the vision of EIL goes beyond mere "connection"; it also addresses another critical underlying capability: privacy.

If EIP-7702 and AA solve "accessibility," then the Kohaku privacy framework released by Vitalik at Devconnect may become the next piece of the EIL puzzle, echoing another core principle in the "Trustless Declaration," which is "anti-censorship."

At Devconnect, Vitalik stated plainly that "privacy is freedom" and indicated that Ethereum is on a path to privacy upgrades, aiming to provide real-world privacy and security. To this end, the Ethereum Foundation has established a privacy team composed of 47 researchers, engineers, and cryptographers dedicated to making privacy a "first-class attribute" of Ethereum.

This means that future privacy protection will no longer be an optional plugin but a fundamental capability as natural as transferring funds. As a realization of this vision, the Kohaku framework has emerged—essentially, Kohaku uses your public key to create a temporary stealth address, allowing you to perform private operations without revealing links to your main wallet.

With this design, future AA accounts will not only serve as asset management tools but also as privacy shields.

By integrating protocols like Railgun and Privacy Pools, AA accounts will allow users to provide "proof of innocence" compliantly while protecting transaction privacy, enabling any user to prove that their funds are not of illegal origin without exposing specific consumption paths to the outside world.

Thus, we can clearly see the full picture of the Ethereum interoperability roadmap:

• OIF (Intent Framework): Making the application layer "understand" user needs;
• EIL (Interoperability Layer): Paving the way for execution at the infrastructure layer.

This may also be a clear signal that the Ethereum Foundation wants to convey: Ethereum should not be a collection of loosely connected L2s but a massive, unified supercomputer.

In the future, when EIL is fully realized, we may no longer need to explain to new users what L2s or cross-chain bridges are; all they will see are assets, without the barriers of chains.