About

ZK-rollups often require high gas fees for proof verification each time a proof is submitted to L1 (e.g., Scroll, Taiko). This sets a relatively high entry barrier for L2 projects that aim to scale Ethereum. It also makes it hard to realize cheap-enough L2 transactions in the short term.

Currently, there are many discussions on further scaling Ethereum by using Layer3 to reduce the gas fee of each transaction (e.g., Fractal Scaling, Taiko’s inception layers). But we can use a different approach to solve this problem through a simpler way, as Vitalik described in this article:

By using recursive ZK proof to aggregate a batch of proofs, only the final proof needs to be verified on the mainnet. This scheme is more concise and thus more robust and easier to understand.

Our Solution

We aim to develop a permissionless protocol, ZKPortal, that addresses the issue of high verification fees for ZK-rollups, while also promoting Ethereum's scaling capabilities.

Via ZKPortal, ZK apps can permissionlessly register by submitting their verifier and callback entry points to the protocol. Then, ZK apps don't need to submit proofs to their contracts. Instead, they could submit proofs to ZKPortal's aggregator contract. A prover can permissionlessly get and aggregate a batch of pending proofs, compute the final proof, and submit it to the aggregator for verification. If the verification passes, each corresponding ZK app entry point is called back, which means related proof is verified. The prover will get compensated from ZK apps or users. ZK apps or users only need to pay a portion of the fee, which is cheaper.

ZKPortal protocol aligns with the vision of ZK-rollups in scaling Ethereum. It can also support a broader range of ZK apps, such as ZK Oracle, ZK Bridge, and privacy ZK apps. As ZK apps blossom, ZKPortal will help the Ethereum ecosystem reduce fees without sacrificing the original security.

Roadmap

• 2023 Q2: White paper
• 2023 Q3-Q4: Protocol V1 – the smart contract and batch prover client
• 2024 Q1: Protocol deployed on Testnet
• 2024 Q1-Q2: Faster batch prover client, cheaper verification algorithm
• 2024 Q3: Protocol deployed on Mainnet

About the Team

We are a dev team founded in 2022. We have enthusiasm for exploring ZK and Ethereum scaling. We have researched and participated in projects like Taiko, Scroll, Aleo, etc.

This idea is still under rapid discussion and design. We will update this page as soon as possible. The project will be developed fully open-sourced on GitHub. We also look forward to discussing and building with everyone who is interested. Keep us posted!