Crypto glossary

zkEVM

A zkEVM is a virtual machine that runs Ethereum-style smart contracts and produces a zero-knowledge proof that every step was executed correctly, so developers can reuse familiar code on a proof-based network.

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EVM plus proofs

The Ethereum Virtual Machine, or EVM, is the engine that executes smart contracts on Ethereum. Every full node re-runs each transaction to check it. A zkEVM executes the same kind of code but also generates a cryptographic proof, a zero-knowledge proof, that the execution followed the rules. Anyone can verify that proof quickly instead of repeating the work.

The original EVM was never designed with proofs in mind. Some of its operations, like the Keccak hash function, are very expensive to prove. Making it provable was long considered one of the hardest engineering problems in the field.

Where zkEVMs are used

Most zkEVMs today power zero-knowledge rollups, layer-2 networks that execute transactions off Ethereum and post a compact proof to the main chain. Examples include Polygon zkEVM, zkSync Era, Scroll and Linea. Because they speak the language of the EVM, developers can often deploy existing Solidity contracts and users can keep using familiar wallets.

Not all zkEVMs are equal

Vitalik Buterin proposed a widely used classification from Type 1 to Type 4. A Type 1 zkEVM is fully equivalent to Ethereum itself, including its data structures, which is the most compatible but slowest to prove. Higher types change internals to make proving cheaper, at the cost of small incompatibilities. A Type 4 compiles high-level code such as Solidity to a different, proof-friendly machine, so some contracts or tools may behave differently.

In practice, compatible usually means most code works, not that every contract and developer tool behaves identically.

Risks to understand

zkEVMs are complex, young software. A bug in the circuit that generates proofs could let an invalid state be accepted. Many networks also still rely on a single operator to order transactions, called a sequencer, and on upgradeable contracts controlled by a small group. Bridging funds to a zkEVM rollup means trusting those components until they mature.

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Frequently asked questions

Is a zkEVM the same as a zk-rollup?

Not exactly. A zk-rollup is the scaling system, and a zkEVM is one kind of execution engine it can use. Some zk-rollups use non-EVM virtual machines instead.

Can I use MetaMask on a zkEVM?

Usually yes. Most zkEVM rollups support standard Ethereum wallets once the network is added, although a few use their own account models.

Why are zkEVMs cheaper than Ethereum?

Many transactions share one proof and one batch of data posted to Ethereum, so each user pays only a fraction of the main-chain cost.

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