# USDC (USDC) Quantum Readiness Report

> USDC has a QRI score of 10/100 and is assessed at Stage 2 (Mitigation / Development) with medium evidence confidence.

Evaluation date: 2026-06-06. Review status: draft. Evaluated scope: USDC stablecoin token across all production host chains, including token-specific admin/governance keys and CCTP bridge attestation. Host-chain user transaction signatures are inherited per QRI §7.2 Token Inheritance. Arc L1 blockchain is excluded as a separate project not in production scope..

USDC scores 10/100 (QRI Stage 2: Mitigation / Development). Circle has published an exemplary post-quantum security whitepaper (May 2026) with comprehensive cryptographic inventory, threat modeling, phased migration strategy, and recovery framework designs — earning full credit for Security Assessment & Evidence Preparedness (5/5). However, zero production PQ protection exists for any token-specific function. All admin key authorization (MasterMinter, Blacklister, proxy-admin, Owner, Pauser) and CCTP bridge attestation remain entirely ECDSA-only. Multiple admin keys have exposed on-chain public keys, creating material long-exposure quantum-vulnerable value-at-risk across ~$76.5B in circulation. User transaction signatures inherit host-chain quantum vulnerability. The Arc L1 blockchain (separate project) plans native PQ support but does not protect current USDC. The whitepaper's proposed dual-signature contract upgrades and recovery frameworks are roadmap items with no production deployment. Score is capped at 40 by the Readiness & Risk Cap (active production spend authorization entirely ECC-only) but the raw Factor Score of ~10 is the binding constraint.

## Core resources

- [USDC QRI report](https://qrindex.org/projects/usd-coin/): Human-readable assessment with score, stage, evidence, blockers, risks, and assurance notes.
- [USDC structured report data](https://qrindex.org/projects/usd-coin/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.
- [USDC official website](https://www.circle.com/en/usdc): Project-maintained website.
- [USDC source repository 1](https://github.com/centrehq/centre-tokens): Project source code referenced by QRI.



## Evidence sources

- [Evidence source 1](<https://6778953.fs1.hubspotusercontent-na1.net/hubfs/6778953/PDFs/quantum_paper.pdf>): Public source cited by the USDC QRI assessment.
- [Evidence source 2](<https://www.arc.io/post-quantum-whitepaper>): Public source cited by the USDC QRI assessment.
- [Evidence source 3](<https://community.arc.io/public/blogs/circles-post-quantum-security-roadmap-securing-blockchains-smart-contracts-and-digital-assets-for-the-quantum-era-2026-05-30>): Public source cited by the USDC QRI assessment.
- [Evidence source 4](<https://github.com/circlefin/stablecoin-evm>): Public source cited by the USDC QRI assessment.
- [Evidence source 5](<https://github.com/circlefin/evm-gateway-contracts>): Public source cited by the USDC QRI assessment.
- [Evidence source 6](<https://developers.circle.com/cctp/references/attestation-verification>): Public source cited by the USDC QRI assessment.
- [Evidence source 7](<https://projecteleven.com/quantum-vs-usdc-threat-analysis>): Public source cited by the USDC QRI assessment.
- [Evidence source 8](<https://invarians.com/audit-trail-for-agents>): Public source cited by the USDC QRI assessment.
- [Evidence source 9](<https://etherscan.io/address/0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48>): Public source cited by the USDC QRI assessment.
- [Evidence source 10](<https://etherscan.io/address/0x10df6b6fe66dd319b1f82bab2d054cbb61cdad2e>): Public source cited by the USDC QRI assessment.
- [Evidence source 11](<https://hackmd.io/oWjl8BJ_R_W5gk2s2Ecbbg>): Public source cited by the USDC QRI assessment.
- [Evidence source 12](<https://circlefin-evm-cctp-contracts.mintlify.app/concepts/attestation>): Public source cited by the USDC QRI assessment.
- [Evidence source 13](<https://usdc.cool/>): Public source cited by the USDC QRI assessment.
- [Evidence source 14](<https://coinmarketcap.com/currencies/usd-coin/>): Public source cited by the USDC QRI assessment.
- [Evidence source 15](<https://www.circle.com/usdc>): Public source cited by the USDC QRI assessment.
- [Evidence source 16](<https://github.com/circlefin/stablecoin-evm/blob/master/doc/tokendesign.md>): Public source cited by the USDC QRI assessment.
- [Evidence source 17](<https://developers.circle.com/cctp/references/technical-guide>): Public source cited by the USDC QRI assessment.
- [Evidence source 18](<https://www.circle.com/blog/preparing-blockchains-for-q-day>): Public source cited by the USDC QRI assessment.