# Arbitrum (ARB) Quantum Readiness Report

> Arbitrum has a QRI score of 4.19/100 and is assessed at Stage 1 (Quantum Risk Assessed) with medium evidence confidence.

Evaluation date: 2026-08-12. Review status: draft. Evaluated scope: Arbitrum One optimistic rollup (Nitro/BoLD), ARB token, canonical bridge to Ethereum L1, AnyTrust DAC (Arbitrum Nova), sequencer, and L1 settlement dependency.

Arbitrum is an optimistic Ethereum L2 rollup whose entire production cryptographic stack is classical: ECDSA secp256k1 for EOAs, the centralized sequencer/batch-poster, and DAS store requests; BLS12-381 for AnyTrust DAC (Nova); and Ethereum L1 for bridge escrow, batch settlement, and BoLD fraud-proof arbitration. Offchain Labs has published no quantum risk assessment, cryptographic inventory, or migration roadmap, and no PQC primitive is deployed anywhere in the Nitro stack. The community has flagged quantum exposure in a forum technical overview, and external evaluators have produced independent assessments, but these are not project-authored. Architectural crypto-agility surfaces exist (EIP-7702, ERC-4337, Stylus WASM precompiles) but are latent and unused for quantum defense. The resulting Factor Score of 4.19 is capped by the absence of a public cryptographic inventory (Readiness & Risk Cap 10), yielding a QRI Score of 4.19 at Stage 1 (Quantum Risk Assessed). Arbitrum's quantum readiness is fundamentally inherited from and bounded by Ethereum L1's own classical migration timeline.

## Core resources

- [Arbitrum QRI report](https://qrindex.org/projects/arbitrum/): Human-readable assessment with score, stage, evidence, blockers, risks, and assurance notes.
- [Arbitrum structured report data](https://qrindex.org/projects/arbitrum/report.json): Complete report as JSON for deterministic machine processing.
- [QRI methodology](https://qrindex.org/methodology/): Scoring model, evidence handling, readiness stages, confidence, assurance, and report status.
- [All QRI project reports](https://qrindex.org/llms.txt): Score-ranked index of every published project assessment.
- [Arbitrum official website](https://www.coingecko.com/en/coins/arbitrum): Project-maintained website.



## Evidence sources

- [Evidence source 1](<https://qrindex.org/projects/arbitrum/>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 2](<https://forum.arbitrum.foundation/t/post-quantum-cryptography-risk-in-arbitrum-smart-contracts-a-technical-overview/31027>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 3](<https://docs.arbitrum.io/intro/glossary>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 4](<https://github.com/OffchainLabs/nitro>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 5](<https://docs.arbitrum.io/audit-reports>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 6](<https://docs.dfns.co/networks/supported-key-formats>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 7](<https://docs.arbitrum.io/launch-arbitrum-chain/configure-your-chain/common/data-availability/data-availability-committees/deploy-das>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 8](<https://docs.arbitrum.io/how-arbitrum-works/deep-dives/anytrust-protocol>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 9](<https://arbitrum.io>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 10](<https://docs.arbitrum.io/how-arbitrum-works/bold/bold-technical-deep-dive>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 11](<https://drops.dagstuhl.de/storage/00lipics/lipics-vol316-aft2024/LIPIcs.AFT.2024.2/LIPIcs.AFT.2024.2.pdf>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 12](<https://docs.arbitrum.io/get-started/arbitrum-introduction>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 13](<https://docs.safe.global/core-api/transaction-service-reference/arbitrum>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 14](<https://docs.arbitrum.foundation/deployment-addresses>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 15](<https://docs.arbitrum.foundation/gentle-intro-dao-governance>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 16](<https://veridise.com/audits/arbitrum/>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 17](<https://github.com/offchainlabs/nitro-contracts>): Public source cited by the Arbitrum QRI assessment.
- [Evidence source 18](<https://github.com/OffchainLabs/stylus>): Public source cited by the Arbitrum QRI assessment.