ZIP-10 ZK Gateway as a Settlement Layer

Abstract

ZIP-10 builds upon the foundation established by ZIP-6, which introduced V26 of ZKsync in preparation for ZK Gateway.

This proposal formally approves ZK Gateway as an optional shared settlement layer within the Elastic Network. Its goal is to improve the efficiency of batch settlements across ZK Chains by lowering settlement costs and offering more stable pricing particularly for chains that do not rely on Ethereum for data availability (DA). Additionally, ZK Gateway will enable future interoperability across the Elastic Network and unlock even lower costs once optimized precompiles are introduced in an upcoming release.

Motivation

1. Cheaper Batch Settlement:
   • ZK Chains that choose to use ZK Gateway will enjoy lower fees for settling transactions.
   • Even cheaper pricing is expected in the future when optimized cryptographic operations (precompiles) are introduced.
2. Interoperability:
   • ZK Gateway can become a trustless communication hub between ZK Chains.
   • Paves the way for cross-chain functionality in the Elastic Network.

Specification

• No new code this builds on the work from ZIP-6 and reuses the existing architecture.
• ZK Gateway will be registered as a valid settlement layer.
• Governance will:
  • Register ZK Gateway with Bridgehub.
  • Set up a ChainTypeManager to manage chains settling on Gateway.
  • Prepare for future migrations and interactions.

Rationale

This upgrade gradually introduces a shared settlement layer that delivers immediate benefits to ZK Chains, including more stable and eventually lower settlement costs especially with future upgrades that bring more efficient cryptographic precompiles. By leveraging the existing, proven ZK Chain architecture, the network can roll out these improvements quickly and reliably.

To learn more into the technical details and governance actions around this proposal, you can read the full ZIP-10 discussion on the ZKsync governance forum here.