# USX (USX) Quantum Readiness Report

> USX has a QRI score of 9.79/100 and is assessed at Stage 1 (Quantum Risk Assessed) with medium evidence confidence.

Evaluation date: 2026-06-06. Review status: draft. Evaluated scope: USX SPL token (contract 6FrrzDk5mQARGc1TDYoyVnSyRdds1t4PbtohCD6p3tgG) on Solana mainnet, including token-specific admin/governance keys. Evaluation inherits Solana L1 QRI per Section 7.2 Token Inheritance..

USX is a standard Solana SPL stablecoin token issued by Solstice Finance with $501M+ TVL. It inherits Solana's quantum-vulnerable Ed25519 signature scheme for all user spend authorization and address exposure. Token-specific strengths include PDA-controlled minting (quantum-resistant by design since PDAs use SHA-256 hashing with no private keys) and claimed non-upgradeable token programs. However, the Squads 3/5 multisig that governs program upgrades, parameter changes, and emergency operations relies entirely on Ed25519 signer keys — a token-specific quantum-critical vulnerability. Solstice Finance has published no quantum risk assessment, cryptographic inventory, migration roadmap, or PQ implementation of its own. The QRI Score of 10 reflects a project where quantum risk is acknowledged only through Solana L1 inheritance, with no meaningful project-level production protection. Users should monitor Solana's Falcon migration progress and Solstice Finance's admin key migration status.

## Core resources

- [USX QRI report](https://qrindex.org/projects/usx/): Human-readable assessment with score, stage, evidence, blockers, risks, and assurance notes.
- [USX structured report data](https://qrindex.org/projects/usx/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.
- [USX official website](https://solstice.finance/): Project-maintained website.



## Evidence sources

- [Evidence source 1](<https://docs.solstice.finance/solstice-for-builders/smart-contracts>): Public source cited by the USX QRI assessment.
- [Evidence source 2](<https://solstice.finance/security>): Public source cited by the USX QRI assessment.
- [Evidence source 3](<https://solana.com/news/quantum-readiness>): Public source cited by the USX QRI assessment.
- [Evidence source 4](<https://www.helius.dev/blog/what-would-solana-need-to-change-to-become-quantum-ready>): Public source cited by the USX QRI assessment.
- [Evidence source 5](<https://github.com/anza-xyz/cryptography/pull/10>): Public source cited by the USX QRI assessment.
- [Evidence source 6](<https://github.com/firedancer-io/firedancer>): Public source cited by the USX QRI assessment.
- [Evidence source 7](<https://blueshift.gg/research/quantum-proofing-solana>): Public source cited by the USX QRI assessment.
- [Evidence source 8](<https://jumpcrypto.com/resources/quantum-migration-paths-for-solana>): Public source cited by the USX QRI assessment.
- [Evidence source 9](<https://quantumwalletcheck.com/learn/solana-quantum>): Public source cited by the USX QRI assessment.
- [Evidence source 10](<https://www.anza.xyz/blog/securing-solana-against-a-powerful-quantum-adversary>): Public source cited by the USX QRI assessment.
- [Evidence source 11](<https://www.helius.dev/blog/solana-post-quantum-cryptography>): Public source cited by the USX QRI assessment.
- [Evidence source 12](<https://solstice.finance/usx>): Public source cited by the USX QRI assessment.
- [Evidence source 13](<https://storage.googleapis.com/dapp_prod/audit_reports/halborn_program_audit_250605.pdf>): Public source cited by the USX QRI assessment.
- [Evidence source 14](<https://docs.solstice.finance/solstice-for-builders/sdk>): Public source cited by the USX QRI assessment.
- [Evidence source 15](<https://github.com/soqucoin/soqtec>): Public source cited by the USX QRI assessment.