Since October of this year, Ethereum co-founder Vitalik Buterin has published a series of articles about the potential future of the Ethereum protocol, covering six parts of Ethereum's development roadmap: The Merge, The Surge, The Scourge, The Verge, The Purge, and The Splurge.
We have previously interpreted the first part of the roadmap (The Merge), and this article will continue to interpret the second part of this series, The Surge, in which Vitalik focuses on Ethereum's scalability and long-term development. From the technical roadmap at this stage, we gain insight into how Ethereum will transform into a protocol capable of handling immense demand (TPS reaching 100,000+), while maintaining decentralization and security.
Ethereum's core vision
Essentially, Ethereum aims to be the foundational layer of a decentralized internet. Ethereum supports complex decentralized applications through automatically executed smart contract code, and this flexibility makes it the preferred blockchain for developers building decentralized applications, including DeFi, NFTs, and more.
However, Ethereum faces limitations in scalability. Ethereum L1 can only handle about 15 to 30 transactions per second, which is a significant gap compared to traditional payment networks like Visa. This results in high gas fees during network congestion and limits Ethereum's capability to become a global-scale infrastructure. This is precisely the issue that The Surge aims to address.
The main goals of The Surge are as follows:
- Ethereum L1 + L2 achieves 100,000+ TPS;
- Maintain the decentralization and robustness of L1;
- At least some L2s fully inherit Ethereum's core attributes (trustless, open, censorship-resistant);
- Maximize interoperability between L2s: Ethereum should function as an ecosystem rather than dozens of different blockchains.
Rollup-centered future
The Surge refers to Ethereum's plan to significantly improve scalability, primarily through L2 solutions. Rollup is a key component of this strategy. The rollup-centric roadmap proposes a simple division of labor: Ethereum L1 focuses on being a robust and decentralized base layer, while L2 takes on the task of helping the ecosystem scale.
Rollup packages transactions off-chain and then submits them back to the Ethereum mainnet, significantly increasing throughput while maintaining security and decentralization. In Vitalik's words, rollup can increase Ethereum's scalability to over 100,000 TPS. This would be a transformative scaling solution as it allows Ethereum to handle global-scale applications without compromising the spirit of decentralization.
Vitalik emphasizes that rollup is not just a temporary solution, but also a long-term scaling solution. Ethereum 2.0 reduced energy consumption by transitioning from PoW to PoS through The Merge, while rollup is viewed as the next important milestone as a long-term scaling solution.
This year, the rollup-centric roadmap has achieved significant milestones: with the launch of EIP-4844 blobs, Ethereum L1's data bandwidth has dramatically increased, and several Ethereum Virtual Machine (EVM) rollups have entered the first stage. Each L2 exists as a shard with its own internal rules and logic, and the diversity and pluralism of shard implementations have now become a reality.
Data availability sampling (DAS) further developments
Another key aspect of The Surge is Data Availability Sampling (DAS), a technology aimed at addressing data availability issues. In decentralized networks like Ethereum, it is crucial that all nodes can verify data without storing or downloading everything.
DAS allows nodes to verify data without accessing the complete dataset, thereby enhancing scalability and efficiency.
Vitalik emphasized two forms of DAS: PeerDAS and 2D DAS.
PeerDAS is expected to enhance the trust assumptions in rollup, making it more secure. 2D DAS samples not only randomly within blobs but also between blobs. By utilizing the linear properties of KZG commitments, a set of new virtual blobs can expand the blob set in a block, encoding the same redundant information.
With DAS, Ethereum can handle larger amounts of data, enabling faster and cheaper rollups without compromising decentralization.
In the further future, more work is needed to determine the ideal version of 2D DAS and prove its security properties.
The long-term reality path envisioned by Vitalik is:
(1) Implement the ideal 2D DAS;
(2) Insist on using 1D DAS, sacrificing sampling bandwidth efficiency for simplicity and soundness by accepting lower data limits;
(3) Abandon DA and fully adopt Plasma as the primary Layer 2 architecture.
Notably, even the choice to expand execution directly at the L1 layer exists. This is because if the L1 layer is to handle a large number of TPS, L1 blocks will become very large, and clients will want an efficient way to verify their correctness, thus they will have to use the same technologies as rollup (such as ZK-EVM and DAS) at the L1 layer.
Plasma and other solutions
In addition to Rollup, one of the early proposed off-chain scaling solutions, Plasma, is another L2 solution.
Plasma creates child chains that handle transactions independently of the main Ethereum chain and periodically submit summaries to the mainnet. For each block, operators send each user a Merkle branch to prove the change in the user's asset state. Users can withdraw their assets by providing the Merkle branch. Importantly, this branch does not have to be rooted in the latest state.
Therefore, even if there are issues with data availability, users can restore their assets by extracting the latest available state. If a user submits an invalid branch (for example, extracting assets that have already been sent to others, or if the operator creates an asset out of thin air), the legitimate ownership of the asset can be determined through an on-chain challenge mechanism.
Although Plasma's development has lagged behind rollup to some extent, Vitalik still views it as part of Ethereum's broader scalability toolkit.
Additionally, Vitalik discusses improving data compression techniques and cryptographic proofs to further enhance the efficiency of rollups and other L2 solutions. The idea is to compress as much data as possible while ensuring all necessary information is still available for Ethereum nodes to verify. These technological improvements are likely to play a key role in Ethereum achieving higher throughput.
The above diagram shows a Plasma Cash chain, where the transaction spending Coin i is placed in the i-th position in the tree. In this example, assuming all previous trees are valid, it is known that Eve currently owns Coin 1, David owns Coin 4, and George owns Coin 6.
Early versions of Plasma could only handle payment use cases, making it ineffective for further scalability. However, if each root is validated with SNARKs, then Plasma becomes much more powerful. The process can be significantly simplified since most potential paths for operator cheating are excluded. At the same time, new paths open up, allowing users to immediately withdraw funds without waiting for a week-long challenge period in the absence of operator cheating.
The above diagram shows one way to create an EVM plasma chain (not the only way): using ZK-SNARK to build a parallel UTXO tree reflecting the balance changes made by EVM, defining a unique mapping of 'the same coin' at different historical periods. Plasma structures can be built on this.
Plasma's performance is quite good, which is a key reason everyone is designing clever structures to overcome its security shortcomings.
Improvements in cross-L2 interoperability
A major challenge currently facing the L2 ecosystem is the weak cross-L2 interoperability, and improving how the experience of using the L2 ecosystem feels like using a unified Ethereum ecosystem is urgently needed.
Improvements in cross-L2 interoperability fall into many categories. Theoretically, Ethereum, centered on Rollup, is similar to executing shard L1. The current Ethereum L2 ecosystem still faces the following issues in practice to reach an ideal state:
Specific chain addresses: Chain information (L1, Optimism, Arbitrum...) should be included in the address. Once this is achieved, the cross-L2 sending process can be realized simply by placing the address in the sending field, allowing the wallet to manage how to send in the background (including using cross-chain protocols).
Specific chain payment requests: A message in the form of 'send me X type of tokens on chain Z' should be easily and standardized to create. There are mainly two application scenarios: payments between people or payments between people and merchant services; dApp funding requests.
Cross-chain exchanges and gas payments: There should be a standardized open protocol to express cross-chain operations. Attempts like ERC-7683 and RIP-7755 exist in this field, although both have broader applications than these specific use cases.
Light clients: Users should be able to actually verify the chain they are interacting with, rather than just trust RPC providers. For example, a16z crypto's Helios can do this (for Ethereum itself), but this trustlessness needs to extend to L2. ERC-3668 (CCIP-read) is one strategy to achieve this.
The shared token bridge concept: Suppose in a world where all L2s are validity-proof rollups and each slot submits to Ethereum, transferring an L2 asset to another L2 in its native state still requires withdrawal and deposit, which incurs significant L1 gas fees.
One approach to solving this problem is to create a shared minimalist Rollup, whose sole function is to maintain which L2 owns each type of token and how much balance each has, allowing these balances to be batch updated through a series of cross-L2 send operations initiated by any L2. This would enable cross-L2 transfers without paying L1 gas fees for each transfer, nor relying on technologies like ERC-7683 based on liquidity providers.
Synchronous composability: Allow synchronous calls to occur between specific L2s and L1 or among multiple L2s. This helps improve the financial efficiency of DeFi protocols. The former can be realized without any cross-L2 coordination; the latter requires shared ordering. Rollup-based technologies automatically apply to all these technologies.
Many of the above examples face the dilemma of when and which layers to standardize. If standardization occurs too early, it may entrench a suboptimal solution. If it occurs too late, it may lead to unnecessary fragmentation.
A current consensus is that, in some cases, there exists a weaker but easier-to-implement 'short-term solution', as well as a 'long-term solution' that is 'ultimately correct' but takes years to achieve. These tasks are not just technical issues; they are also (and perhaps primarily) social issues that require cooperation between L2, wallets, and L1.
Continue to scale Ethereum L1
Vitalik believes it is very valuable to expand Ethereum L1 itself and ensure that it can continue to accommodate an increasing number of use cases.
There are three strategies for L1 scaling, which can be pursued individually or in parallel:
(1) Improve technologies (e.g., client code, stateless clients, historical expiry) to make L1 easier to verify, then raise the gas limit;
(2) Reduce the cost of specific operations while increasing average capacity without increasing worst-case risk;
(3) Native Rollups (i.e., creating N parallel copies of EVM).
These different technologies each have their trade-offs. For example, native rollups have the same weaknesses in composability as ordinary rollups: they cannot send a single transaction to synchronously execute operations across multiple rollups. Raising the gas limit may undermine other benefits that can be achieved through simplified L1 verification, such as increasing the user proportion running verification nodes and increasing the number of solo stakers. Depending on the implementation method, making specific operations cheaper in EVM may increase the overall complexity of EVM.
Decentralization and security
The balance between scalability and decentralization is one of the themes Vitalik has repeatedly mentioned. Many blockchain projects choose to sacrifice decentralization for higher throughput. For example, Solana can handle thousands of transactions per second but requires powerful hardware to run nodes, leading to centralization of the network. Vitalik insists that even as Ethereum continues to scale, it must maintain its commitment to decentralization.
Rollup and DAS are seen as methods to increase Ethereum's capacity while maintaining its decentralized nature. Unlike Solana or other high-performance blockchains, Ethereum's scaling strategy ensures that anyone can run a node to genuinely decentralize the protection of the network. This is crucial to Ethereum's vision of establishing a blockchain that can support a global, permissionless financial system.
The higher the scalability, the greater the responsibility regarding security. As Ethereum moves towards a rollup-centric future, ensuring the trustlessness of these systems becomes crucial. Rollup relies on cryptographic proofs to ensure that off-chain transactions are valid when submitted back to Ethereum. Although these systems have proven effective, they are not without risks. Vitalik acknowledges that the maturity of these technologies requires rigorous testing and iteration, especially as they are adopted more widely.
The Surge's outlook
After The Surge, Vitalik envisions Ethereum being not only scalable but also fully decentralized, secure, and sustainable. This vision includes not only scaling Layer 1 through rollup and DAS but also building more efficient consensus algorithms, improving developer tools, and nurturing a thriving dApp ecosystem.
Ethereum's roadmap is optimistic, yet there are many challenges. Mass implementation of rollup, ensuring the security of L2 solutions, and preparing for a quantum future are all complex tasks. However, if Ethereum can successfully overcome these obstacles, it will solidify its position as the core of Web3: a decentralized, user-controlled internet.
In the rapidly evolving blockchain space, Ethereum focuses on scalability without sacrificing decentralization, which is its uniqueness. If The Surge succeeds, it may reshape the landscape of blockchain technology once again in the coming years.
