Zero-knowledge rollups (ZK rollups, ZK-rollups, ZKRs) have emerged as a cutting-edge phenomenon in the realm of Web3. The pivotal role they play in scaling Ethereum has propelled their widespread adoption during the period of 2022–2023.

In the ensuing discourse, GetBlock aims to elucidate the fundamental principles underpinning ZK rollup primitives while showcasing the preeminent projects that harness their potential for DeFi applications.

Exemplary ZK rollup projects in 2023: Key Aspects ZK rollups exhibit a novel approach by offloading certain transactional data from the Ethereum mainnet, thereby preserving its computational resources and enhancing the efficiency of its operations.

Zero-knowledge rollups encapsulate cryptographic technology that facilitates data aggregation and verification. ZK rollups enable Ethereum-based systems to partially process data outside the network’s mainnet. Utilizing a ZK-based framework, data compression takes place, consolidating information pertaining to thousands of transactions into a singular entity, subsequently verified within the Ethereum ecosystem. To safeguard the integrity and confidentiality of information, ZK rollups generate zero-knowledge proofs. By leveraging ZK rollups, decentralized applications (dApps) can harness the power of Ethereum at minimal costs and significantly accelerated speeds compared to direct interactions with its mainnet. StarkNet, zkSync, and Aztec have emerged as prominent implementations of ZK rollup technology. Prominent Web3 behemoths such as Coinbase and Polygon Network have launched their zkEVM networks, seamlessly integrating Ethereum’s code while utilizing ZK rollups for data processing. Leading dApps including Aave, Uniswap, dYdX, and Curve have successfully deployed their respective versions on ZK-based systems. In light of its limitations and obstacles, ZK rollup technology stands out as the most promising avenue for scaling Ethereum in terms of transaction throughput and usage costs.

In what way can ZK rollups facilitate the scalability of Ethereum? ZK rollup systems rely on three essential components to ensure their secure and efficient operation:

Ethereum network’s smart contract: This smart contract acts as the intermediary between the scaling solution and Ethereum itself. Every transaction processed within the ZK rollup system needs to be mirrored on the main network.
Third-party prover: The prover plays a crucial role by generating cryptographic proofs to guarantee the validity and integrity of the data processed through the ZK rollup system. It is imperative that the data remains uncompromised during the compression process. Additionally, the entire procedure is executed in a ‘zero-knowledge’ manner, ensuring that no party gains access to the transferred information.
Verifiers ecosystem: Verifiers, a subset of blockchain validators, assume the responsibility of confirming the status of the proofs and submitting them to the Ethereum mainnet.
In essence, ZK rollups employ data compression techniques to process thousands of transactions on Ethereum as a single transaction, offering enhanced speed and cost efficiency. Throughout this process, ZK rollups strive to safeguard data from unauthorized access or tampering.

Notable ZK rollup projects in 2023: A Comparative Overview Projects falling under the ‘ZK rollups’ category can be broadly classified into two main groups. The first group consists of blockchains that utilize ZK rollup technology to scale Ethereum.

The second group encompasses applications that leverage ZK rollups, similar to how they previously utilized Ethereum or Polygon.

Here are a few examples of ‘ZK rollup’ blockchains:

1. StarkNet
2. zkSync
3. Polygon zkEVM
4. Aztec
5. Scroll Now, let us summarize the fundamental aspects of some notable ZK rollup projects in 2023.

Now, let’s review some of the most trending implementations of ZK technology, its advantages, challenges and limitations.

StarkNet

An Innovative Solution StarkNet, crafted by the pioneering Web3 developers at StarkWare Labs in Israel, emerged as one of the earliest functional ZK-based systems within the Ethereum landscape.

StarkNet: An Overview Coded in Cairo, an original programming language, StarkNet stands as a permissionless ZK rollup blockchain. The brainchild of Eli Ben-Sasson, the inventor behind the Zero-Knowledge Scalable Transparent Argument of Knowledge (ZK-STARK) protocol, StarkNet made its debut in early 2018.

In 2020, StarkNet introduced its initial implementation, StarkEx, aimed at scaling the operations of select Ethereum decentralized applications (dApps) such as Rhino and Sorare.

StarkNet: Key Features StarkNet’s architecture encompasses three crucial off-chain components: the Sequencer, Prover, and Full Node. The Sequencer receives user transactions, the Prover batches them together while generating cryptographic validity proofs, and the Full Nodes track the system’s status changes.

Furthermore, the platform incorporates two on-chain elements: the Verifier, which handles cryptographic proofs, and StarkNet Core, responsible for ensuring L1-L2 consistency through system updates.

StarkNet: Advantages ZK-STARK, the underlying technology of StarkNet, is widely recognized for its heightened security and scalability in comparison to other scaling solutions like Optimistic Rollups. Notably, StarkNet envisions the future inclusion of additional Provers to enhance its capabilities.

Moreover, StarkNet boasts inherent quantum resistance and offers greater flexibility for customization.

StarkNet: Limitations Certain researchers have voiced criticisms concerning the design of the StarkNet smart contract, which establishes its connection to Ethereum, as well as the limitations associated with the interactions between the Sequencer and Prover components.

zkSync

Pioneering Innovation Created by Matter Labs, zkSync made its initial debut in June 2020, under the name zkSync Lite, and has since become a prominent player in the ZK rollups domain in 2023.

zkSync: An Overview zkSync presents an innovative approach to scaling Ethereum through its ZK rollups solution. Currently, it comprises two distinct blockchains: zkSync Lite, previously known as zkSync 1.0, and zkSync Era, formerly referred to as zkSync 2.0.

zkSync 1.0: A Groundbreaking Implementation Pioneering the realm of ZK technology, zkSync 1.0 achieved a remarkable milestone by attaining a nine-digit Total Value Locked (TVL). It stands as the first commercially viable implementation of ZK technology, making waves in the ZK rollups sphere.

zkSync Era: Unveiling a New Era Introducing zkSync Era, the world’s inaugural zkEVM blockchain, which enables ZK-based Layer 2 (L2) networks to seamlessly execute code written for the “native” Ethereum Virtual Machine (EVM). This remarkable feature, known as “EVM equivalence,” opens up new possibilities for application compatibility.

zkSync: Innovative Features zkSync, since its version 1.0 release, has harnessed the power of PLONK (Permutations over Lagrange-bases for Oecumenical Non-Interactive Arguments of Knowledge). This advancement eliminated the need for application-specific trusted setups, replacing them with a universal and updatable setup. This upgrade significantly streamlines dApp development efforts, reducing both time and resources.

In addition to EVM equivalence, zkSync 2.0 presents an intriguing infrastructure, comprising the traditional set of Full Node, Prover, and Interactor, accompanied by a Paranoid Monitor. This monitor serves as a vigilant guardian, promptly alerting Matter Labs of any potential incidents.

zkSync: Advantages Distinguished as the first ZK rollup project to potentially support sharding through its zkPorter protocol, zkSync opens the door to enhanced scalability. Furthermore, it offers support for multiple smart contract languages beyond its internal Zinc language.

zkSync charges users with exceptionally low fees, earning it the distinction of being the second most cost-effective option, according to L2Fees Info, as of Q2 2023.

zkSync: Limitations In March 2023, certain users reported sluggish L2-to-L1 withdrawals on the zkSync 2.0 network, highlighting a temporary drawback that warranted attention.

Polygon zkEVM

Empowering Ethereum’s Future The revolutionary Polygon zkEVM emerges as the inaugural zkEVM solution crafted by the esteemed blockchain ecosystem, Polygon Network (MATIC).

Polygon zkEVM: A Closer Look In March 2023, the world witnessed the launch of Polygon zkEVM, a groundbreaking solution that seamlessly blends 100% EVM-equivalence with the security and resource efficiency of ZK proofs. Ethereum- and Polygon-based dApps can effortlessly migrate to the L2 blockchain without the need to modify their existing codebases.

Polygon zkEVM: Unveiling Unique Features Distinguished for pioneering the practical application of recursive STARKs, Polygon zkEVM has achieved remarkable advancements. This breakthrough has resulted in a staggering 100-fold improvement in the performance of the most resource-intensive operations within the zkEVM, including Keccak, ECDSA, and Recursion. Additionally, the Prover component of Polygon zkEVM showcases exceptional capabilities, efficiently validating 500K gas units on a modest CPU server (64 cores) in just 300 seconds.

Polygon zkEVM: Leveraging Advantages The complete equivalence with EVM, encompassing all EVM ecosystem blockchains, solidifies Polygon zkEVM as the go-to solution for dApps seeking to transition away from L1 networks. Furthermore, it benefits from the robust “ecosystem effect” of Polygon, the largest EVM-compatible blockchain, fostering a thriving environment for growth and innovation.

Polygon zkEVM: Considering Limitations While Polygon zkEVM enjoys wide acclaim, some users have raised concerns about the role of MATIC tokens in zkEVM operations. Additionally, the fee structure has been a topic of discussion, as it is perceived as comparatively higher than that of many competitors.

Aztec

Pioneering Privacy Solutions Introduced in 2021, Aztec stands as the pioneering ecosystem of L2 solutions, emphasizing privacy in Ethereum transactions, thereby unlocking opportunities for both private and public smart contracts.

Aztec: Exploring its Uniqueness Aztec proudly presents itself as the first-ever hybrid ZK rollup, combining multiple layers of ZK infrastructure. One layer encrypts transactions, ensuring privacy, while the other layer compresses transactions before forwarding them to Ethereum.

Aztec: Highlighting Features Aztec relies on its own smart contract language, Noir, setting it apart from competitors. Unlike its counterparts, Aztec is not EVM compatible, operating independently from the Ethereum Virtual Machine. The protocol employs a state tree based on the Unspent Transaction Output (UTXO) model, alongside a public state tree, resembling Ethereum’s familiar Patricia-Merkle tree structure. Additionally, it boasts a zero-knowledge execution environment.

Aztec: Embracing Advantages Aztec’s key strength lies in its unwavering commitment to prioritizing privacy in all smart contract operations, enabling developers to integrate private states seamlessly into their designs.

Aztec: Considering Limitations While Aztec offers exceptional privacy features, it lacks support for Solidity, the mainstream programming language for Ethereum-based dApps. Moreover, amidst intensifying regulatory scrutiny, privacy solutions like Aztec may face increased attention from law enforcement agencies worldwide.

Scroll

Advancing Ethereum’s Landscape Similar to Polygon zkEVM, Scroll represents an Ethereum-compatible zkEVM-based ZK rollup, ensuring 100% equivalence with the Ethereum ecosystem. It serves as an ideal solution for migrating L1 dApps.

Scroll: Unveiling its Journey Introduced in 2021, Scroll steadily approaches its mainnet release. Despite being in the testing phase, its value has already surpassed $1.6 billion after recent funding rounds. As with other zkEVM products, Scroll champions EVM equivalence as its standout feature.

Full article: https://getblock.io/blog/top-zk-rollup-projects-of-2023-review/