From the LBank blog.
On the 20th of July, Polygon announced that they made a giant leap forward for Ethereum scaling and ZK innovation- Polygon zkEVM. Also, they released a complete implementation, fully open-source of it.
There are two major approaches to scale Ethereum by Layer 2 Rollup- Optimistic Rollups and ZK Rollups. In a rollup system, contract state hashes are stored on-chain, along with the transaction calls and arguments logged as call data. Rollup performance is gained by batching many off-chain transactions into a single on-chain state transition- easy to understand why it is faster.
Layer2s like Arbitron and Optimism are optimistic rollups. Aggregators submit roll-up blocks that summarize the off-chain transactions; anyone can check the validity of the roll-up blocks and issue a dispute to let the on-chain contract execute the call data to verify the roll-up blocks.
Layer2s like Loopring and Starkware are ZK rollups. It is similar to Optimistic Rollup but relies on ZK-SNARKs for block verification instead of on-chain disputes. However, for a long time, Zk rollups were quite challenging and complicated, and expensive. Even a small adjustment to function needs lots of effort on change to the underlying circuits.
This is a huge gap between the devs and zkrollips. Few devs were willing to build on ZKrollups until they could actually run their solidity code on ZKrollup- It all depends on zkEVM.
So what are the zkEVM competitors on the market right now?
First of all, as we mentioned at the beginning, Polygon, the sidechain of Ethereum, released its first zkEVM. Polygon zkEVM leverages the fastest ZK tech with plonky2, while giving users and devs the convenience of EVM-equivalence. EVM-equivalence means that any smart contract or dev tool that you can use on Ethereum can be used on Polygon zkEVM.
Another one is Scroll. On the 19th of July, they released their pre-alpha version zkrollup which is zkEVM-based for external testers. If you’d like to be an early tester, sign up at https://signup.scroll.io for access. This initial release will be run on a private PoA fork of Ethereum (the testnet L1) operated by Scroll with some basic functions.
What’s more. Also on the 20th of July, zkSync announced their first zkEVM rollup will be live on mainnet in 100 days.
What runs on Loopring and Starkware are zkrollups but not zkEVM.
With all these amazing development of zkEVM, we can tell that a fully functional one will release soon! All these competitors will push this to happen even sooner.
This article came directly from the LBank blog, found on https://lbank-exchange.medium.com/zkevm-is-coming-c7a84102dd05?source=rss-87c24ae35186——2