- Optimism rollup supersedes zk-rollup when it comes to scalability and costs
- Zk-rollup has an upper hand when considering gas fees and transactional costs.
- zk-rollup has a higher latency for users than optimism
Roll-ups are considered to be layer-2 scaling solutions that are created to confront the scalability challenges of blockchain networks, specifically Ethereum. There are various types of rollups. Two of the prominent ones are optimistic rollups and zk-rollups.
Understanding ZkSync
(Zero-Knowledge rollups) is a prominent layer-2 scaling solution. It handles the scalability issue of the Ethereum blockchain. In the framework of zkSync, transactions are handled off-chain and then augmented into a single proof for the final submission to the fully developed Ethereum protocol for verification.
zkSync facilitates various improvements in transaction throughput, reduced fees and robust privacy, with the perk of maintaining the prolonged security and decentralization of the Ethereum network. However, there are also a few limitations to zkSync, as it is not equipped with intensive resources to implement zero-knowledge proofs (ZKPs)
Understanding Optimism
Optimism Network uses the foundation of optimistic rollups to build a framework that can facilitate its scaling technology. It aggregates various transactions into a single monolith or batch and similar to zkSync, it processes them off-chain. On the foundation of optimistic rollups, there is Optimism network and on top of the Optimism network is a layer of OVM (Optimistic Virtual Machine).
OVM facilitates the verification of transactions for the Optimism network. While the scalability has significantly improved, the whole mechanism of the Optimism Network is still dependent on the Ethereum mainnet for the final validation of transactions. The insurance of a robust security paradigm comes at the compromise of dependency on the mainnet.
Optimistic Rollups Vs Zk-Rollups
When it comes to scalability and costs, optimistic roll-ups have a clear-cut advantage in sustaining higher transaction throughput. They are preferred over zk-rollups in cases of applications that require fast and frequent transactions. One of the side-effects of this is, however, the implementation of higher gas fees.
zk-rollups have an upper hand when it comes to gas fee savings, thus incorporating lower transaction costs. But that does not affect the computational cost, which is fairly high on the rollup chain. On the other hand, while considering costs, optimistic roll-ups are more compatible with the Ethereum infrastructure. Optimistic rollups facilitate the developer’s ability to leverage smart contracts without any major modifications.
There is a risk factor associated with the Optimistic roll-ups, as censorship attacks driven by a fraudulent sequencer or validator can manipulate or delay the submission of valid transactions to the Ethereum main chain. Such malicious activities disrupt and tamper with the ideal transactional flow, resulting in harm to users’ funds.
Conclusion
Layer-2 scaling solutions for Ethereum are developed by the combined contribution of both zkSync and Optimism rollups. There is no clear-cut answer to which of these two rollups has the upper hand. In the end, it comes down to grasping an understanding of the specific requirements and trade-offs associated with each solution. Once the needs and priorities of projects are figured out, it will be easier to identify which rollup to choose between Optimism and zkSync.