ZkEVMs are a unique type of zero-knowledge (zk) rollup – that functions on the Ethereum network. They process transactions and enable efficient interactions on the network. These rollups offer users several benefits including low-cost transactions. So, in this article, we will explore the zkEVM innovation; how it works; the various types of zkEVMs; a study of the ecosystem, and take a closer look at the problems it solves.

The Need for zkEVM

Critics of Ethereum have lamented how slow it is, which has been seen to increase over the years. Only 10-15 transactions can be processed per second by the core protocol, which during periods of intense user activity, has led to network congestion and high transaction fees.

The Ethereum community is actively growing, and during the past months, several scaling strategies have gained popularity. A variety of solutions have been explored by developers, including sidechains, which move transactions to a second layer (L2) where they are quickly processed before being directed back to the primary chain.

This has historically been effective for individual applications, but there is an issue since many of these side chains employ rollups that are referred to as “optimistic.”

Although there are many methods, not excluding side chains from developers, Layer 2 (L2) solutions have long been at the forefront of the scaling conversation. A Layer 2 solution of this nearly perfect nature has been progressively seen “live” in the market with continuous improvements. Zero-knowledge rollups seem to be in the spotlight now.

The Zero-Knowledge Ethereum Virtual Machine, also known as zkEVM, is one of the most promising technologies in the Ethereum ecosystem. This project aims to enhance the Ethereum Virtual Machine’s functionality while also making a significant technological advance that will protect our privacy when we interact with smart contracts that use this new EVM.

At least as of 2014, zkEVMs were initially enthusiastically explored, and now the technology is almost usable. They are being constructed by major Ethereum development companies like Polygon and Scroll, and others are rushing to follow suit.

Please Note: Sidechains (e.g. Polygon, PoS) are secondary chains that operate in parallel to a parent chain with their consensus mechanism; they are connected to the parent chain by a two-way bridge.

What Is ZK?

ZK is an acronym for zero-knowledge, which we can call a cryptographic word for one party being able to prove to another that something is true, without leaking any other information. In essence, it enables the exchange of private data while maintaining its secrecy.

Zero-knowledge proofs grant a user the ability to reveal his knowledge of a secret without actually revealing that secret. This is basically to identify and show you are speaking the truth. The prover and verifier play the two primary roles in zero-knowledge proofs. The prover must demonstrate knowledge of the secret and the verifier confirms the prover is stating the truth.

What Is zkEVM?

As a part of zero-knowledge (ZK) rollups, the Zero Knowledge Ethereum Virtual Machine (zkEVM) creates zero-knowledge proofs to confirm the accuracy of programs as well as the reliability of inputs and outputs utilized in the operation. They are L2 scaling solutions for Ethereum that increase throughput through off-chaining computation and state storage. ZkEVMs are created with zero-knowledge technology in mind, allowing them to carry out smart contracts.

ZK-rollups are beginning to enable Ethereum DApps with the introduction of zero-knowledge virtual machines that are compatible with EVM.

This will allow developers to write or migrate smart contracts while maintaining the decentralization and security of Layer One’s (L1s) without having to alter their code or give up their EVM tools (and smart contracts).

Having learned what zkEVM is, let’s probe further and break down the complexity behind zkEVM, starting with understanding EVM.

Ethereum Virtual Machine (EVM)

Ethereum is a technology that is known for enabling open and distributed virtual computer execution. A deployed Ethereum smart contract cannot be updated and is open to hostile inspection.

Smart contracts are used in the majority of applications (auctions, prediction markets, identity/reputation management, etc.) to handle funds or authenticate external entities. The code ought to be reliable in this setting.

How Does the EVM Work?

The Ethereum Virtual Machine operates as a state machine that changes its state in response to inputs. Every time a smart contract is executed, the EVM’s state changes, or there is a “state transition.” In addition to smart contracts, which are all of these Solidity programs that we can see on the blockchain, we have software repositories for the DApps projects that we are familiar with.

Here, we take a look at what occurs during transactions in smart contracts:

1. Peer-to-peer nodes on the EVM load and execute contract bytecode, which was generated from the source code.

2. EVM Opcodes are instructions that are executed by the Ethereum Virtual Machine in executing smart contracts on the Ethereum blockchain. They interact with various state components of the EVM through the bytecode (memory, storage, and stack).

3. Before returning the new values, EVM opcodes compute the values taken from state storage.

NB: The EVM Opcode is an abbreviation for Ethereum Virtual Machine Operation code, which is a part of the machine language instructions that give commands on the operation to be performed.

zkEVM Ecosystem

Although zkEVM announcements may have buzzed developers and stakeholders who are keen on privacy and scalability, most of these projects are far from completion.

Considerably, these projects face several challenges other than just going live. As zkEVMs take advantage of changes in Ethereum, they will expand their coverage, and gradual improvements will follow once most of these projects are launched.

There will certainly be other projects of this nature shortly, but these are the largest and most developed. Ultimately, the development of the blockchain seems unstoppable, as projects like zkEVM demonstrate.

The Importance of zkEVM

The creation of a fully working zkEVM will promote the creation of ZK-rollup projects that are EVM-compatible. This offers the following benefits:

1. Secure scalability: ZK-rollups provide stronger security assurances than other scaling efforts; they use validity proofs to confirm the accuracy of off-chain computing.

2. Lower costs: By publishing transaction data to Ethereum as CALL DATA, rollups obtain protection from the Mainnet. The amount of data that optimistic roll-ups and ZK-rollups must broadcast to Ethereum varies. Further lowering the need for CALL DATA, the zkEVM may even skip transaction inputs and publish just final state changes.

3. A zkEVM has no issues that others do have, leading to quicker finality and capital efficiency. Power users that require smooth asset switchings, such as NFT traders, DeFi investors, or arbitrage traders, will benefit from faster finality (especially between L1 and L2).

4. Network effects: Taking use of Ethereum’s network effects is the main justification for creating EVM-compatible zkEVMs. Ethereum, which is the largest smart contract platform, offers a fairly large ecosystem and this is good for both developers and crypto projects. We should also note that if a newly built zkEVM isn’t compatible with Ethereum’s infrastructure, its network effects cannot be utilized.

zkEVM and EVM Compatibility

What we can observe in the EVM and its derivatives, which includes the zkEVM, is the aforementioned procedure. EVM and zkEVM differ most significantly in that the latter creates a secure execution environment that is protected from outside agents, even if they are on the same network.

The runtime environment used to execute smart contracts installed on the Ethereum network is known as the EVM (Ethereum Virtual Machine). On the Ethereum blockchain, decentralized apps (DApps) are operated using the EVM, which serves as a sort of “world computer.”

But with zkEVM, this drastically changes. In a ZKP environment, the input data are visible, but they are a sequence of data produced by ZKP cryptography rather than the actual data. Consequently, the data input essentially consists of a sequence of statistics that the zkEVM may use to confirm that what we assert is correct without ever disclosing the actual information that led to those data.

ZkEVMs can execute Ethereum smart contracts without making significant modifications to the underlying logic, making them EVM-compatible.

How Does zkEVM Work?

The overall operation of zero-knowledge rollups is followed by zkEVMs. However, it is crucial to recognize that several theories surround the optimum design of a zkEVM and how it functions. The purest form of zkEVMs would be Ethereum-equivalent and would not permit any modifications, even if they helped simplify proof production.

A zkEVM is a virtual machine that undergoes state changes as a result of program actions, similar to the EVM. However, the zkEVM goes a step further by offering proof to support the accuracy of each calculation component.

We must accept the variety of zkEVMs to comprehend how they operate, as evidenced by the active initiatives. Although they all have the same objectives, their methods are different.

What Problem Does it Solve?

Because standard EVMs can only understand rollups separately, there is no universal programming language and ZK rollups must be created from scratch.

Projects Building on zkEVM

Various zkEVM projects, such as Scroll, Polygon, Nethermind, The Privacy, and Scaling Explorations, use various strategies to combine EVM execution with the computation of zero-knowledge proofs. Every approach has its special tradeoffs. Every project continuously works to develop a Layer 2 scalable solution that is reliable, safe, secure, affordable, and simple to use.

All of these projects share the same fundamental objective: utilizing ZK-SNARK technology to create cryptographic proofs of execution of transactions similar to those of Ethereum, either to make the Ethereum chain itself much easier to verify or to create ZK-rollups that are (almost) equivalent to what Ethereum offers but are much more scalable. However, these initiatives differ slightly in terms of the compromises they are making between expediency and practicality.

Recent Development

In contrast to zkSync, most zero-knowledge EVMs are still in development and the prospect of fully functional zkEVMs is better than ever, as zero-knowledge technology develops.

In the meantime, StarkNet’s zero-knowledge virtual machine allows developers to take advantage of zero-knowledge applications. As far as StarkNet is concerned, it is not EVM-compatible, but it can compile solidity source code to bytecode in a ZK-friendly format. Also, contracts can be written in Cairo (StarkNet’s language).

Conclusion

zkEVM can provide a similar experience for both developers and users. Several levels of activity can be used to improve scalability, where the zkEVM can be seen as a mend to the tear on these issues in the crypto space. Together, users and builders can be said to expect a greater level of improvement and advancement due to the breakthrough in zero-knowledge rollups against reducing scalability issues, including security, and also supporting contract deployment and application compatibility.

Just like its counterpart innovation, zkSync, the zkEVM is pretty much still in its developmental stage and a work in progress, which makes it quite unclear in deciding what the future fully holds for Ethereum.