Is L2 really protected by Ethereum?

Author: Ishita Source:HazeflowTranslation: Shan Oppa, Bitchain Vision

Ethereum’s growth over the past decade has been shaped by a simple commitment: scaling the network without compromising decentralization.According to its roadmap, the answer is a Rollup-centric future—the Layer 2 network (L2s or “Rollups”) executes transactions off-chain to achieve lower costs and higher throughput while still getting core security from Ethereum as the underlying layer (Layer 1).

Almost all major Rollups, such as Arbitrum, Optimism, Base, zkSync and Scroll, advertise themselves as “security provided by Ethereum.”This phrase is powerful and powerful, at the heart of its marketing narrative, but is it in line with reality?This statement becomes obscured once you look closely at how Rollup actually works and how assets flow in.

This article will analyze the gap between slogans and reality, starting with a bridge (where the user funds are located), followed by a sorter (who will sort transactions), and finally a governance mechanism (who will make rules).

The reality of the Rollup Bridge

The statement that “security provided by Ethereum” ignores the way users actually interact with these systems.

To use Rollup, whether it is for DeFi, payments, or applications, your assets need to exist on it first.Ethereum does not have a built-in method to move in or out assets directly; you can’t simply “transmit” ETH into Rollup.This requires aBridge.Bridges are inlets and exits between Ethereum and Rollup, which define the security that users actually experience.

How the bridge works

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When you deposit ETH to Rollup, you send it to a bridge contract on Ethereum.This contract locks your ETH and tells Rollup to create an equal amount of tokens in your L2 wallet.For example, if you deposit 1 ETH, the bridge will securely hold your 1 ETH on Ethereum, while your Rollup account will display 1 ETH.Since Ethereum holds locked ETH, deposit isMinimize trustof.

take out

Extract the complexity of the operation.To exit, the process is the opposite:

1. You destroy (or lock) the tokens on Rollup.

2. You send a message to the Ethereum bridge contract: “I destroyed the token on L2, please release my locked ETH.”

The key is:Ethereum cannot see what is happening inside Rollup.It is blindly sceptical about L2 calculations.

Therefore, Ethereum will only provide withdrawals on the bridge.proveOnly when your funds will be released.The proof can be:

• Proof of fraud (Optimistic Rollup):Assume that the transaction is valid unless challenged during the dispute period.

• Proof of validity (ZK Rollup):A crypto proof that pre-existing that all transactions comply with the rules, so Ethereum can trust the results immediately.

• Multiple signatures or committee:Rely on trusted parties for proof.

The bridge defines how you access Rollup.Think of it as a window of the house.Even if the windows (bridges) are broken, the house (Rollup) itself remains standing.But if the windows are broken, you can’t get in and out safely.Similarly, a damaged bridge cuts out the user’s access, even if the Rollup machine itself is still running.

This is why the bridging layer measures Rollup securityReal lens.Assets “Security Provided by Ethereum”Is it trueSecurity depends on the bridge you use and the trust model you rely on, not the Rollup itself.

Bridge model and its assumptions

• Canonical Bridges (“official” Rollup Bridge):They are bound to Ethereum.When you lock the asset here, the Ethereum validator guarantees that you can eventually retrieve L1, even if L2 stops running.Specification bridge isonlyA bridge that directly inherits Ethereum security attributes.

• External Bridges (such as Wormhole, LayerZero, Axelar):They provide faster user experience and cross-chain transfers through independent validator committees or multi-signature mechanisms, but are not enforced by the Ethereum consensus.If these off-chain operators are hacked or colluded, users may lose money even if Ethereum runs perfectly.

• Native Issuance (Native Issuance, tokens minted directly on Rollup):For example, USDC on Base or OP on Optimism.These assets have never passed the specification bridge and cannot be redeemed on L1.Their security comes from Rollup’s governance and infrastructure,InsteadEthereum.

Where are the Rollup assets actually stored?

As of August 29, 2025, Ethereum Rollups has locked in total$43.96 billionassets.The subdivision is as follows:

• External bridge:$16.95 billion (39%)—The largest category

• Specification bridge:$14.81 billion (34%)—Assets secured by Ethereum

• Native casting:$12.20 billion (27%)— Rollup native assets

Trends over time

Looking back from 2019 to 2022, normative bridging was the primary force driving Rollup adoption.Almost all early growth came from the official bridge that put Ethereum at its core.

However, from the end of 2023, things have begun to change:

• The normative bridging continues to grow in absolute terms and peaks in 2024, but its share begins to shrink.

• Native issuance has expanded steadily, especially from 2024 to 2025.

• External bridging accelerated the fastest from the end of 2023, and by the beginning of 2025, theyBeyond specification bridge——This is the intersection of Ethereum’s loss of majority share of Rollup assets.

today,Two-thirdsThe Rollup assets (external bridge + native) are within the scope of Ethereum’s direct securityOutside.

Rollup Level Segment

The market is highly concentrated: Rollup, the top six, accounts for 93.3% of the total TVL.In these ecosystems, the allocation is as follows:

• Specification bridging: 32.0%

• Native release: 28.8%

• External bridge: 39.2%

Aggregation mode diagram

• External focus:Arbitrum and Unichain, users pursue rapid exit/liquidity through third-party bridges.

• Specification focuses on:Linea (and the slightly lesser extent OP Mainnet), more L1-source collateral is routed through official bridges.

• Native Focus:zkSync Era and Base, a large number of assets issued on L2 (such as native USDC on Base) and direct deposit channels.

importance:In the largest Rollup, most of the value lies outside the direct guarantee of Ethereum.The security that users actually obtain depends on the bridge model behind each part of the assets.

Beyond the Bridge: Other Risks

The bridge explains where the asset is located, but even if each asset is standardized, users still face other trust and security gaps.The following three areas are most important: how transactions are sorted, who governs the stack, and how composability affects the user experience.

1. Sorter: Centralized control point

Sorting is the sequential process of incorporating transactions into the blockchain.Almost most Rollups useCentralized sorter.This setup is fast and profitable.

But the centralized sorter can:

• Review transactions, by refusing to include it in the block.

• Block withdrawals indefinitely, because it determines when the exit request will be submitted to Ethereum in batches.

• Completely offline, stop activity until it resumes operation.(For example, Arbitrum experienced a 78-minute downtime).

Ethereum incorporates a “forced inclusion” mechanism that allows users to submit transactions directly to L1 to bypass the sorter.But these mechanisms do not guarantee fairness.The sorter still controls block sorting, which is usually enough to harm the user’s interests.

Here is an example of a transaction that can be included but still fails:

1. Suppose you are trying to withdraw funds from Aave on L2.

2. You submitted a forced included withdrawal request on Ethereum, which means the sorter cannot ignore it.

3. But the sorter can insert its own transaction before your transaction—for example, borrowing additional funds from the same pool.

4. By the time your withdrawal is running, the pool of funds is no longer liquid enough and your withdrawal fails.

Your transaction is “included”, but its results are destroyed.

Forced inclusion also presents practical troubles: waiting times can be as long as several hours (sometimes over 12 hours), limited throughput, and the risk of still being reordered after commit.It is more like a slow safety valve than a guarantee of fair execution.

At the same time, the driving force for decentralization is forming.Projects such as Espresso and Astria are building a network of shared sorters to improve resilience and interoperability.

One key idea here isPre-confirmation: The sorter or shared network will include the early commitments made to the transaction, even before the transaction is finalized on Ethereum.This helps reduce the delay penalty caused by decentralization and allows users to get faster guarantees without sacrificing neutrality.

However, centralized sorters still dominate because they are simple, profitable, and attractive to institutions—at least until competition or user demand forces change.

2. Governance and incentive risks (corporate L2s)

It is really important who runs L2.Many leading Rollups are run by companies or venture-backed teams (such as Coinbase’s Base, Offchain Labs’ Arbitrum, OP Labs’ Optimism).

Their obligations are first and foremost to shareholders/investors, not to Ethereum’s social contract.

• Shareholder Responsibility → Profit Pressure:Fees are initially lower to attract users, and once liquidity and apps are locked in, fees will rise (classic “platform tax” model).Higher sorter fees, preferential integrations or rules that benefit operators’ broader business are expected.

• Locking effect → Leverage:After accumulating billions of TVL and users, the conversion cost makes exiting difficult.Operators can change economic models or policies without worrying about large-scale migration.

• Cultural mismatch:Ethereum relies on public developer meetings, multi-client diversity, and open governance (EIPs).Corporate Rollups are more top-down, often with management keys/multi-signatures that can be paused, upgraded, or frozen – putting compliance or profitability above neutrality.Over time, Rollup may become more and more like a walled garden.

The result is that the gap between Ethereum’s open spirit and the incentives to shape corporate Rollup is growing.This gap not only affects governance, but also spreads to how applications interact and how users experience the system.

3. Composability and User Experience (UX)

The “magic” of Ethereum lies inAtomic Composition: Contracts can be read/write synchronously in a transaction (imagine: a Uniswap redemption can atomically repay Aave and trigger a Maker action).L2s breaks this composability:

• Asynchronousness:There is a delay in cross-rollup messages, specification bridge exit can take several days, and third-party bridges add trust assumptions.

• Isolated Island:Liquidity and state fragmentation between L2, reducing the seamless DeFi user experience that makes Ethereum compelling.

What can solve this problem?

Ethereum native Rollup(Designed and governed according to the L1 standard) Synchronous reads of L2→L1, synchronous writes of L1→L2, and atomic-level cross-rollup writes, thereby restoring most of L1’s composability while expanding the block space.Without this, user experience will continue to lean towards those convenience layers that are not provided by Ethereum’s security.

The Future of Rollup

If “security provided by Ethereum” wants to go beyond a slogan, then core assurance must reside on L1, not in off-chain committees or in a sorter controlled by a single company.There are three designs that point in this direction.

Native RollupTransfer validity entirely to Ethereum.

• Rather than giving users a trust in a standalone fraud proof system, a ZK prover who they cannot audit or a security committee, Rollup will provide a transaction trajectory that Ethereum itself can re-execute.

• In fact, this turns withdrawals and status correctness into L1’s right, not a promise: if Rollup claims your balance is X, Ethereum can check this claim directly.

• This narrows the attack surface of the bridge, reduces the need for pause keys, and aligns Rollup with future Ethereum upgrades.

• The cost is that it costs more on L1, but the reward is simple: when a dispute occurs, it is decided by L1.

• No native Rollup is available yet.

Based RollupAnchors transaction sorting to the collection of validators for Ethereum.

Today, a single sorter can reorder or delay transactions, which in practice is enough to undermine the “forced inclusion” mechanism.

With the Base L1 consensus sorting, the canonical sorting comes from L1, so review and last-second reordering becomes much more difficult.

Forced inclusion becomes a normal path rather than a slow safety valve.The project adds “pre-confirmation” to keep the user experience fluent while still having L1 as the final arbitrator of the sort.

You’ll give up some L2 revenue and flexibility, but you’ll remove the largest single point of control in the current stack.

The core team dedicated to the design of Based Rollup include Taiko, Spire and Puffer.

Keystore RollupAddresses a more hidden but persistent source of risk: keys and upgrades.

Instead of having each Rollup (and app) handle account recovery, session keys, and rotations, a minimal “keystore” Rollup normalizes the logic once and syncs it all over the place.

Users rotate or recover keys in one place; changes propagate to all L2s.Operators need fewer emergency keys; administrators also need fewer “God Mode” switches.

The result is that wallets are stolen, the hasty escalation after the incident has occurred, and the separation between account security and application logic is clearer.

The design of the keystore Rollup is only a theory and has not yet been launched.

All in all, these approaches are consistent with the problems users actually face: trust-dependent exit mechanisms, sorting controlled by a single company, and fragile key/upgrade paths.

Rollup is included in the Ethereum umbrellawinThe way to the statement “security provided by Ethereum” is not just about using it as a promotional slogan.