In the previous days, we have discussed The Surge and The Scourge, the second and third stages of the Ethereum upgrade. We learned what these upgrades are focused on, how they will work, and what issues they address on the existing Ethereum network.

In continuation of this five-part post-Ethereum Merge article, we now discuss the fourth phase of the Ethereum upgrade — The Verge. Let’s all learn what it does to the network, how it works, and what improvements we can expect.

The Verge explained

The Verge phase gets its name from what it will introduce to the network: Verkle Trees.

Verkle trees, another method of tackling the issue of scalability, are a “powerful upgrade to Merkle proofs that allow for much smaller proof sizes,” according to Buterin.

The Verge upgrade is set to reduce the amount of data that network validators have to store on their machines by using Verkle trees.

The Verkle trees are part of a broader roadmap for making Ethereum stateless — another complex concept that is still evolving. In its essence, the proposal aims to introduce stateless clients, where validating nodes don’t have to store state data before verifying blocks. It will lower the hardware requirements for running a node, strengthening the decentralization and resilience of the Ethereum network. The concept was first proposed by Buterin in 2017 and is still undergoing research and development by the community.

During the Verge, storage on the network will be optimized and node sizes will be reduced. In the end, this will help make Ethereum more scalable.

How does it work?

Aside from Verkle Trees, The Verge will work with the implementation of forks.

Introducing Verkle Trees

Verkle trees do require more complex cryptography to implement, but they present the opportunity for large gains to scalability. Their introduction will optimize storage and let users become network validators without storing large amounts of data on their machines. Instead of needing to provide all “sister nodes” at each level, the prover needs only to provide a single proof that proves all parent-child relationships between all commitments along the paths from each leaf node to the root.

The suggested roadmap includes three hard fork upgrades that will set the ground for achieving the goal of the Verge and the changes required for statelessness.

Shanghai Hard Fork Upgrades

The first upgrade that will happen is named “Shanghai”. Its purpose is to make changes to the gas cost and bring the cost for state access closer to the cost of witnesses. According to the official roadmap, this is needed to be implemented before switching to verkle trees as gas fees are an important signal for optimization to smart contract developers and will prompt them to take action.

The next hard fork “Shanghai+1” will amend the commitment scheme. During the upgrade, the Merkle Patricia Trees (MPT) current state root will be frozen and a Verkle tree commitment will be added, which will be initially empty. All state changes from that point onward will be recorded to this root, and will not affect the frozen MPT.

The actual replacement of the frozen MPT root with Verkle tree root will happen during the second upgrade “Shanghai+2”. These two upgrades are technically complex to execute and if they pose technical challenges, the community may have to postpone them.

The goal is to achieve “optimal statelessness” leading to reasonably small witness sizes that are quick to verify and easy to produce, typically taking a few seconds to compute.

This is all set to help to decentralize the network further.

Initial Thoughts

In a more recent Twitter post by Buterin that provided an update to the Ethereum roadmap, the developer stated that, “The Verge is not just about “verkle trees”, it’s about “verification”. Essentially, the endgame is “fully SNARKed ethereum.”

Once fully implemented, we can expect a faster verification and transaction process in the Ethereum network, while maintaining efficiency and ease of use at a fraction of a cost than what used to be during the pre-Merge era.