Ethereum researcher: How to build native zkEVM on Ethereum Layer1?

Original title: "Ethereum L1 zkEVM》

Original author: polynya, Ethereum researcher

Original Compilation: Kate, Marsbit

Original Compilation: Kate, Marsbit

There seems to be a common misconception that Ethereum can only scale through L2. I might get some blame for writing too much about L2 Rollup and not enough coverage of the L1 expansion roadmap, for which I apologize - here I am trying to correct that mistake, now that L2 has been Well understood, accepted and adopted. Especially Arbitrum One, which has proven itself to be the second largest smart contract chain after Ethereum L1.

But first, a worse version is that "ETH" can only be scaled with L2. To be clear, ETH as a monetary asset can be extended through L1, side chains, other L1, L2, L2-like structures such as validum and optimistic chains, and even through CEX and centralized service providers .

There are millions of ETH bridged to L2 and non-L2 chains, and millions more bridged to non-blockchain venues. Yes, ETH on L1 and (mature) L2 give you native security guarantees, but even though other solutions may have different security assumptions, they can still scale ETH or ether assets. As an aside, in fact, Bitcoin is a perfect example of an asset that scales primarily through centralized services, and it remains the dominant asset in the industry. Remember - for an asset to have value, all you need to do is convince the top 1% of people, families and institutions to believe in it.

Of course, this does not mean that Ethereum can scale, my point is that ETH or Ethereum must be distinguished from Ethereum. Now, there is a further nuance here. For example, BSC expands Ethereum's technology stack, it does build a bridge between ETH and ERC-20, but some people may argue that it cannot expand Ethereum's network.

Leaving that aside, let's get back to the problem of upgrading Ethereum L1 to zkEVM. Actually, before that, the usual disclaimer — I'm an amateur blogger, I know nothing about how blockchain development works, and I don't even know if what I'm saying is even possible. So, consider it an armchair lover's daydream.

Scaling blockchains using ZKPs is an old concept. I don't know when it was first talked about, but I believe it was about Bitcoin, long before Ethereum itself. ZK-SNARKing Ethereum also predates the concept of Rollup. Of course, research into ZK-SNARKing Ethereum went into overdrive when ZK Rollup proved the concept with Loopring in Q1 2020 and then with StarkEx and zkSync (now Lite) and Mina in Q2 . In 2021, I believe Matter Labs popularized the term "zkEVM" and it stuck. The Ethereum Foundation's Privacy and Scaling Exploration team was the primary innovator of the L1-zkEVM, and was later joined by Scroll, Consensys, Taiko, and other contributors.

Is it zkEVM, ZK-EVM, ZkEVM, Zkevm? Who knows, let's call it zkEVM.

So, how will the L1 zkEVM upgrade work? There are many ways to do this, but here's my take. Again, I don't know if this will work, so let's take this as concept art.

The first step is to look at Type-2/2.5 and Type-1 zkEVM Rollup to battle-test the concept in production - upcoming projects include Scroll, Linea(?) and Taiko, reducing verification time and more. The next prerequisites are EIP-4844, statelessness, and PBS (these are happening in parallel, so saying "next" might be misleading). (Note: Of course, zkEVM can do without these, but I will just talk about how I see it here, just like the above.)

Next, I want to look at the Enshrined zkEVM bridge. This will allow Type-1 zkEVM to be deployed on top of L1. This will be a battle test of the exact code and zk circuitry that will eventually be used for the L1 zkEVM. It also allows L2 to exist fully decentralized without any smart contracts, which effectively embodies the L2 zkEVM Rollup. They will be plugged into the PBS infrastructure, with the builders acting as sequencers. All you need is an honest builder. These builders will sort the blocks and commit each slot to L1. This means that the end result of these enshrined Rollups will be the same as L1. This will also open up interesting new possibilities, such as atomic composability between these enshrined Rollups.

It's worth noting that Type-1 zkEVM Rollups can exist outside of such a closed zkEVM bridge - such as Taiko - so maybe we can differentiate them by calling them Type-0? To clarify, these codes are the same codes used for future L1 upgrades.

Once they are battle-tested in production, the L1 execution layer is ready for the zkEVM upgrade. The builder will order the transactions again, generate a proof and submit the proof and data to the consensus layer. Note that for L1 zkEVM, proofs are now verified on the consensus layer. The builder can generate not only validity proofs, but also verkle/state proofs and data availability/kzg proofs. Non-builder nodes then only need to verify these proofs, effectively validating a large number of TPS, including L2, L3, etc., all of which are proved by a single succinct proof of L1 zkEVM, and one proof can rule them all. or on a smartphone or laptop.

The Enshrined zkEVM bridge will continue to exist above the L1 execution layer. Another way is to move it to the consensus layer, and we can have many enshrined L1 Rollups. But I think the best way is to have a canonical enshrined L1 Rollup. BTW, I used to call them "canonical rollups" in 2021, and I later saw Justin Drake refer to the same idea as "enshrined Rollups", a nomenclature that has stuck to this day. So anyway, you have an L1 enshrined Rollup, a lot of Type-0 enshrined L2 Rollups on top, and of course, legacy L2 and sovereign Rollups.

At this point, it's important to note that enshrined L2 Rollup has its own set of tradeoffs. When this happens, the zkEVM will be so slow, with throughput and feature limitations, that we probably only upgrade every few years, if at all. There will also be no governance or sovereignty - they will be entirely enforced by Ethereum node runners. So the innovation will always be on the legacy L2, in a mature state it will have 99% of the benefits without any drawbacks and I expect 90% of the users will continue to use them. Traditional L2, L2-like hybrid versions such as validiums or optimistic chains, enshrined L2 and enshrined L1 Rollup, all offer different trade-offs and features to the user, and I believe that all combined, they will be able to satisfy future decades almost all needs in the blockchain ecosystem.