What is zkEVM and How Does It Work?

As the world of blockchain technology continues to evolve, new innovations and developments are constantly emerging. One of the latest developments in this space is the zkEVM, which is short for zero-knowledge Ethereum Virtual Machine. In this article, we will explore what zkEVM is and how it works.

Before diving into zkEVM, it is important to understand what Ethereum Virtual Machine (EVM) is. Ethereum Virtual Machine is a virtual machine that acts as an smart contract executor of the Ethereum blockchain. Smart contracts are  computer programs with predefined  terms of the agreement between actors who interact with the smart contracts. The smart contract needs to be compiled to the EVM bytecode before it can be executed on EVM, whenever an actor interacts with the smart contract, EVM will execute the corresponding bytecode of given data from the actor.

zkEVM is a new development in the world of blockchain technology that aims to increase the privacy and scalability  of smart contract execution. With zkEVM, you can execute the smart contract off-chain meanwhile the result is succinct and verifiable by on-chain smart contract.

The "zk" in zkEVM stands for zero-knowledge. Zero-knowledge proofs (ZKPs) are cryptographic protocols that enable a user to prove the validity of a computation trace without revealing any additional information about the input and output except the correctness of the computation. 

At the moment, the state of smart contracts is still public, however, with the implementation of zkEVM in the future, we may expect there is no disclosure regarding smart contract’s state.

In traditional smart contract execution on the Ethereum blockchain, the EVM executes the EVM  bytecode contained within the contract address and the results of the execution are verifiable to all nodes on the network by repeating the computation at their EVM. This means that the actual data contained within the contract is visible to anyone who has access to the blockchain.

With zkEVM, the zero-knowledge proofs are used to prove the correctness of the computation performed by the EVM without revealing any information about the inputs or outputs of the computation. When a user wants to execute a smart contract using zkEVM type1 for instance, all they need to do is execute the bytecode with a given input data.  zkEVM will perform the computation then EVM will return the result and a Zero-Knowledge Proof. In order to validate the results of the execution, the zero-knowledge proof in the previous step can be verified independently by a ZKP verifier (it can be a smart contract which was designed to verify ZKP),  by which the smart contract execution can be verified without leak of data.

One of the biggest advantages of zkEVM is the increased privacy and scalability. By using homomorphic encryption  to encrypt the  input, output and the data within smart contracts, zkEVM ensures these sensitive data is not visible to anyone.

zkEVM can be used to serve privacy dApp where nothing is disclosed except the correctness of the dApp execution. Stealth transactions, anonymous voting, anonymous DeFi, etc. would benefit from zkEVM.

As you may know, smart contract execution is considered expensive where a single transaction will be recomputed by thousands of nodes, however, with zkEVM, you can create a proof of the execution of the given transaction and also create proof of validity of the block. zkEVM can be used to improve Layer-1 verification and also can be used to build Layer-2 zkEVM-rollups.

While zkEVM has a lot of potential, there are also some challenges that need to be addressed. One of the biggest challenges is scalability. zkEVM requires a significant amount of computational power to prove zero-knowledge proofs. This can slow down the transaction process and make it more expensive.

Another challenge of zkEVM is the complexity of the design of zkEVM itself, zkEVM considers as a gigantic circuit. Zero-knowledge Proofs are a relatively new technology, and many developers are still working to understand how they work and how to implement them effectively. Therefore, R&D is a barrier for small companies to adopt ZKP and zkEVM in an early stage.

Despite the challenges, zkEVM has a lot of potential in the world of Web3. As the technology continues to evolve and more development toolchains will be available, it is likely that we will see more widespread adoption of zkEVM in the future.

One area where zkEVM could have a significant impact is in the development of decentralized finance (DeFi) applications. DeFi is a rapidly growing industry, and security and scalability are critical components of DeFi applications. By using zkEVM, DeFi applications can ensure the scalability and security of user data  even if the smart contracts were executed privately.

Another potential application of zkEVM is in the development of digital identity solutions. Digital identity is becoming increasingly important in the digital age, but the current solutions are often centralized and vulnerable to hacks and data breaches. By using zkEVM, it may be possible to create decentralized and secure digital identity solutions that protect user privacy while ensuring the validity of user data.

New proving system namely Nova and SuperNova could improve current implement of zkEVM and make zkEVM proving process is more efficient.

In conclusion, zkEVM is a new development in the world of Web3 that aims to provide the security and scalability of smart contract execution. zkEVM ensures that sensitive data is not visible to anyone on the network. While there are challenges associated with zkEVM, such as scalability and complexity, the potential benefits are significant. As the technology continues to evolve, it is likely that we will see more widespread adoption of zkEVM in the future.