ZK Settlement Is Coming to Arbitrum With a Multi‑Proving Model Built for

• Arbitrum introduces a multi-proving model with ZK technology that reduces withdrawal times on its L1 from days to hours.
• The system integrates ZK proofs directly into BoLD, the $ARB settlement protocol toward Ethereum, without eliminating existing fraud proofs.
• The validator was rewritten in Rust as an independent service and the ZK code is being merged into the main Arbitrum Nitro codebase.

Arbitrum announced progress in the implementation of a multi-proving model based on zero-knowledge (ZK) technology, with the goal of reducing settlement times for assets on L1 from seven days to a few hours. The initiative is part of a roadmap presented in early 2026, aimed at establishing the platform as reference infrastructure for financial products in the programmable economy.

The announcement was published by researcher Daniel Lumi and details six technical milestones already achieved. The first establishes that network blocks can be proven via ZK: the system takes a real mainnet block and generates a zero-knowledge proof using SP1, the zkVM developed by Succinct, executing the same state transition function as the current optimistic prover.

Arbitrum ZK and the Future of BoLD

A central point is the integration of the ZK system with BoLD, the protocol that $ARB uses to settle toward Ethereum. Under the expanded scheme, an assertion can be confirmed as soon as a valid ZK proof is submitted and a new Fast Confirmation Committee endorses it, without needing to wait for the full challenge period. BoLD’s dispute game remains active as a fallback layer: if no ZK proof arrives, the chain settles exactly as it does today. ZK proofs, attestations and fraud proofs operate together under a single mechanism.

Another crucial advancement is the extension of the prover to cover Stylus contracts, which extends the EVM with support for Rust, C/C++, Move and other languages that compile to WASM. Arbitrum presents itself as the first production stack to make both EVM and WASM contracts executable by ZK.

Multi-Proving in Production

The network validator was rebuilt as an independent service in Rust, eliminating the Go layer that previously wrapped it. This allows standard validation and proof generation to share a single interface. In parallel, the ZK code is being migrated from an experimental branch into the main Arbitrum Nitro codebase.

Next steps include reducing costs and latency through Reth-based execution, proving the L1 message inbox to ensure end-to-end verifiability, and enabling ZK settlement configuration as a native option in nodes. Offchain Labs will bring a proposal to the DAO to upgrade Arbitrum One under this new scheme.