Leading ZK-rollup blockchains like Starknet, ZKsync, and Polygon boost scalability and security, enabling developers to create products with quick speeds and low costs. Before aggregating and submitting them as a single transaction on the Ethereum main chain, these Layer 2 solutions carry out transactions off-chain.
The leading Ethereum ZK-rollup projects, including dYdX, Sorare, Immutable, Deversifi, and Celer, have made significant strides in lowering costs and producing frictionless user interfaces for wallets, decentralized exchanges, decentralized applications, and more. Zero Knowledge Proof blockchain technology provides an innovative way to verify transactions and data authenticity without revealing sensitive information, enhancing security and privacy in the digital realm.
In this tutorial, we will examine the idea of zero-knowledge rollups and discover their operation. We’ll also discuss their advantages and disadvantages, contrast them with optimistic rollups, and identify some of the most prominent ZK-rollup initiatives active in the blockchain today.
What are ZK-rollups?
On top of a “classic” Layer-1 smart contract blockchain network like Ethereum, a rollup is a Layer-2 scaling solution. They address the conflict between high gas prices and limited throughput, enabling users to pay lower gas prices and blockchains to process transactions more quickly. The zero-knowledge approach is one of the most successful ways these Layer-2 solutions address the scalability and transaction cost issues.
A zero-knowledge rollup (ZK-rollup) is a Layer-2 scaling solution that holds assets in an on-chain smart contract while processing transactions, running computations, and storing data off-chain. Blocks and transactions are validated on-chain by standard Layer-1 blockchain platforms like Ethereum. These same operations are carried out off-chain via ZK-rollups, which then transmit a list of the verified activities to the blockchain. This increases throughput on L1s like the Ethereum mainnet by updating the state of the Layer-1 blockchain while storing a small portion of the overall data.
How does a ZK rollup work?
We need to consider how ZK-rollups are built, utilizing Ethereum as the basic settlement layer, to comprehend how they operate, at least in terms of the most well-known ZK-rollup initiatives.
The “main” contract and a verifier contract, two on-chain smart contracts, are the foundation of the conventional ZK-rollup, constructed on top of Ethereum. These contracts serve as anchors and are in charge of numerous tasks. The main contract manages the status of the blockchain, saves roll-up blocks, and keeps account of fund deposits and withdrawals. On the other hand, the zero-knowledge proofs submitted to the Ethereum mainnet are verified by the verifier contract.
In a typical ZK-rollup, the second layer is occupied by an off-chain virtual machine. As was previously indicated, ZK-rollups execute transactions in an off-chain setting independent of Ethereum. An off-chain virtual machine, which functions as Layer 2 and is the main element enhancing scalability and throughput, is the off-chain environment.
Using an off-chain virtual machine, ZK-rollups process batches of transactions, posting a validity proof on-chain to verify their actions. Zero-Knowledge Proof Services provide secure and privacy-enhancing authentication solutions in the digital age.
Features of a ZK-rollup Project
- Inside Mechanisms
Three pillars support ZK-rollups. Zero-knowledge validity proofs, state commitments, and transactions make up this system.
The validity proof provides cryptographic evidence that the planned changes to Ethereum’s state are the final result of carrying out every operation in the batch. A zero-knowledge proof is a type of cryptographic technique that enables one to demonstrate the veracity of a claim without disclosing any additional information. With this strategy, more transactions are possible while maintaining security to thwart fraudulent transactions, which are frequent in DeFis.
- Smart Contracts
Smart contracts for ZK-rollups were created just a few years ago. This made it possible for the project to manage trickier token trades and transfers.
- Scalability of Blockchain
Like the ZK rollup project, rollups can offer the best scalability options, but they come with important security and trust presumptions. Scalability’s major goal is to increase transaction throughput and speed while preserving decentralization and security. The significant and widespread adoption of Ethereum depends on increased system bandwidth in terms of speed and throughput, or the number of transactions per second.
- Security and Privacy
ZK-rollups offer greater security than the current rollup techniques. Zero-knowledge roll-up Technology is created with some degree of anonymity. This is a result of transaction data only serving as validation evidence and not being placed individually on the base layer.
This rollup project is technically capable of enabling underground asset transfers at the IP layer by default. At some point, it can also tell the difference between a private smart contract and a public one.
ZK-rollups’ Internal Workings
The setup for ZK-rollups consists of transactions, state commitments, and zero-knowledge validity proofs.
- Users of ZK-rollup certify transactions before sending them to the Layer-2 operator. This operator is in charge of all Layer-2 block production tasks, including publishing compressed data on-chain and validating transactions.
- Two Merkle trees represent the accounts and balances of the ZK rollup. The rollup’s accounts and balances change states after each batch of transactions. Merkle roots are used to represent this updated state and are subsequently transferred to the Layer-1 blockchain.
- The blockchain’s state cannot be changed once the operator submits a new state root to Ethereum unless they can demonstrate that the root represents legitimate revisions to the rollup’s state. The operator demonstrates the validity of the batched transactions using a zero-knowledge validity proof. Additionally, one validity proof can support several validity proofs, reducing space.
ZK-rollup Project Advantages
- Zero Knowledge Proof Blockchain uses trustless cryptographic configurations to ensure their security. Optimistic rollups rely on trustworthy validators and sequencers, therefore, trustless crypto methods are a safer bet.
- Authenticating off-chain transactions with validity proofs will stop users from making erroneous changes to Ethereum’s state.
- They maintain security, decentralization, and censorship resistance by keeping compressed transaction data on-chain, which updates the state of their host Layer-1 blockchains.
- Because ZK-rollups only require the blockchain to check validity proofs supplied by the sequencers, transaction finality timeframes are shorter.
- There are hardly any withdrawal delays, and consumers can utilize their funds more effectively.
- Excellent data compression techniques help to cut the cost of publishing data on-chain, which lowers user fees.
- In order to preserve their assets, several sidechains and scaling solutions typically demand that users validate the blockchain. Since ZK-rollups don’t rely on liveness assumptions, they don’t demand such efforts.
Closing Thoughts
ZK-rollups will continue to exist. Even after Ethereum’s update, they will continue to promote scalability, lower transaction costs, and bring other benefits like anonymity by default in specific circumstances. This was done on purpose because the Ethereum network relies heavily on these alternatives to advance.
As they make use of Ethereum’s security model, they offer stronger security than other rollup alternatives, but having a fair share of disadvantages including the potential for censorship and centralization. It’s also important to note that a number of ZK-rollup initiatives are already attempting to address these difficulties, and they are by no means insurmountable. ZK-rollups will be essential in ensuring the survival of various decentralized services and use cases as the crypto ecosystem expands. As a result, it’s not entirely improbable that they may swiftly advance from being a relatively specialized area of knowledge to a staple of common crypto jargon.
