On Wednesday, a trio of unaffiliated companies said they have made progress toward building zero-knowledge protocols capable of scaling Ethereum.
Ethereum sidechain Polygon released the source code for its Polygon zkEVM, short for zero-knowledge Ethereum virtual machine.
Matter Labs, the company behind zkSync, unveiled a roadmap for zkSync 2.0 and plans to launch “the first zkEVM rollup” by year’s end. And Scroll, a company calling itself “the native zkEVM,” said it was releasing the “pre-alpha version” of its protocol.
Polygon co-founder Mihailo Bjelic said that zkEVM takes it one step closer to the “holy grail of scaling.”
A zkEVM would have “all the properties we ideally want/need,” he tweeted, “but it has been considered very hard (or even impossible!) to build!”
Zero-Knowledge Proofs
Zero-knowledge (ZK) rollups are one of many methods that companies have adopted in their attempts to reduce congestion on the Ethereum network, while also improving transaction speeds and reducing transaction costs.
In cryptography, ZK proofs offer a way for one party (the prover) to prove to another party (the verifier) that they are in possession of certain information, without revealing the information itself. This is done through one or more tests offered by the verifier which can only be passed by someone who possesses the required information.
In practice, this means that gas-intensive transactions can be processed on the rollup network with just the final result recorded on Ethereum’s mainnet, greatly reducing congestion.
Matthew Green, a professor of computer science at Johns Hopkins University, has called zero-knowledge proofs “one of the most powerful tools cryptographers have ever devised.”
“If fully realized, zero-knowledge proofs would allow us to prove statements,” Green wrote in a primer on the subject, “while provably revealing no information beyond the single bit of information corresponding to ‘this statement is true’”.
Ethereum Compatibility
“Early ZK-rollups lacked the ability to execute smart contracts and were constrained to simple token swaps and payments,” blockchain developer platform Alchemy said in an introduction to the technology. “But, with the introduction of EVM-compatible zero-knowledge virtual machines, ZK-rollups are starting to support Ethereum dApps.”
Polygon emphasized the point on Wednesday.
“EVM-equivalence means that any smart contract or dev tool that you can use on Ethereum can be used on Polygon #zkEVM. Period,” the company said. “It’s just like using Ethereum, but with the groundbreaking scaling power of ZK tech.”
zkSync 2.0
Matter Labs said its zkEVM would support Solidity and Vyper, programming languages used by Ethereum developers.
“No security re-audit required,” it said in a blog post addressed to developers. “Porting is effortless: 99% of tooling will work out of the box.”
Matter Labs launched zkSync 2.0 on a public testnet in February, and called it “the first ever zkEVM implementation.” A “baby alpha” version will be available to some in November, and a “full alpha” will be “available for all projects and users” by the end of the year.
Scroll, meanwhile, said its “pre-alpha testnet” will be “the first chance for early users and developers to interact with our infrastructure and experience dapp workflows on Scroll.”
Some Twitter users commented on the back-to-back-to-back announcements Wednesday.
“So is every zk rollup announcing zk EVM this week?” tweeted Trenton Van Epps, a self-described “ecosystem person” at the Ethereum Foundation.
Ryan Sean Adams, the founder of Bankless, put it more simply. “It’s zk rollup season,” he tweeted.