Rethinking Ethereum's Scalability: The Possibilities of L1 zkEVM

It is widely believed that Ethereum can only be scaled through L2, but this view may be a misunderstanding. While the focus has previously been on L2 Rollup, it is now time to reassess the L1 scaling roadmap. This discussion is particularly important in the context of Arbitrum One becoming the second-largest smart contract chain after Ethereum L1.

Firstly, it needs to be clarified that ETH, as a monetary asset, has various expansion paths. In addition to L1 and L2, it can also be expanded through sidechains, other L1s, structures similar to L2 (such as validum and optimistic chains), and even centralized service providers. Although ETH on L1 and mature L2s offers native security guarantees, other solutions can also expand ETH or Ether assets, albeit with potentially different security assumptions.

It is worth noting that the value of an asset does not entirely depend on its method of expansion. For example, Bitcoin primarily expands through centralized services, yet it remains the dominant asset in the industry. This indicates that the key to an asset's value lies in gaining recognition from affluent groups and institutions.

However, ETH or Ether needs to be distinguished from the Ethereum network itself. Some scaling solutions may extend the technological stack of Ethereum, but they are not necessarily considered to have extended the Ethereum network itself.

Next, let's explore the possibility of upgrading Ethereum L1 to zkEVM. This concept has a long history, with discussions about applying ZKP to blockchain scalability dating back to before the birth of Ethereum. With the feasibility of ZK rollup being proven in 2020, research on zkEVM has entered a phase of rapid development.

The implementation of the L1 zkEVM upgrade may go through the following stages:

1. Test Type-2/2.5 and Type-1 zkEVM rollup in the production environment.
2. Implement prerequisites such as EIP-4844, statelessness, and PBS.
3. Deploy the Enshrined zkEVM bridge, allowing Type-1 zkEVM to run on top of L1.
4. Upgrade the L1 execution layer to support zkEVM.

In this process, builders will play a key role in ordering transactions, generating proofs, and submitting them to the consensus layer. This will enable non-builder nodes to efficiently verify a large number of transactions, including L2, L3, and so on, all achieved through a single concise proof from the L1 zkEVM.

In the future, we may see a standardized enshrined L1 rollup, along with multiple Type-0 enshrined L2 rollups and traditional L2s. This architecture provides users with different trade-offs and functional choices, and is expected to meet the various needs of the blockchain ecosystem for decades to come.

Nevertheless, we must also recognize that such large-scale expansion may not be necessary. A more conservative approach might be to maintain the current state of L1. In any case, we are at the tail end of this decade, and future developments remain full of possibilities. Although details may change over time, the spirit of exploration and innovation will continue to drive the Ethereum ecosystem forward.