Three clocks to Q-Day. What would still be exposed if it arrived?
Data encrypted today can be harvested now and decrypted later. QER measures that exposure as the overlap of three clocks: when quantum capability arrives, when migration completes and when the data stops mattering. It is a pre-pilot framework for cyber insurers to evaluate, not a price.
Exposure is the overlap of three clocks
When capability arrives
A distribution over arrival times, updated as evidence changes. No single Q-Day date is needed.
When migration completes
How long vulnerable key establishment persists, judged on evidence rather than plans.
When consequence ends
How long compromise still matters. Deleting your copy doesn't remove one harvested earlier.
Constraints that make it defensible
- Key establishment, not signatures. Only KEM/DH migration reduces HNDL exposure. Signature migration is tracked as a separate, forward-looking authentication risk.
- Evidence, not intent. Declared plans, technical observations and production evidence carry different weight. Strong evidence over narrow scope can't establish the whole estate.
- Evidence expires. Favourable technical evidence lapses after a provisional 30 days unless re-observed. Adverse findings don't expire.
- Monotone migration. A demonstrably stronger migration state can never show more exposure because two fitted curves cross.
- Q-Day is a common event. Separate records and shared providers can't create artificial diversification across a portfolio.
- Relative, not absolute. RARI compares an account with a governed benchmark. It is not a premium multiplier.
What's borrowed, what's ours
External sources supply the cryptographic threat, the post-quantum standards and the migration guidance. The modelling propositions are QER's own and remain provisional. Citing a source does not imply its endorsement.
| Component | Source | Status |
|---|---|---|
| Quantum threat to public-key cryptography | Shor, 1994 | external foundation |
| Post-quantum standards | NIST FIPS 203, 204 and 205 | external standard |
| Transition timelines | NIST IR 8547; NCSC migration timelines (2025) | external guidance |
| Readiness and long-secrecy-life data | CISA, NSA and NIST, Quantum-Readiness (2023); NCSC, Next Steps (2023, updated 2024) | external guidance |
| Sector-level HNDL exposure | Garcia, Marcelino and Rufino, IEQ Technical Report 2026-S1 | related technical work |
| Cryptographic inventory tooling | Tenev, qrp-mcp (2026) | related technical work |
| Three-clock exposure structure | QER white paper | our approach |
| Evidence, coverage and expiry adjustments | QER white paper | our approach |
| Key-establishment and signature split | QER white paper | our approach |
| Common-driver and concentration treatment | QER white paper | our approach |
| Severity separation and RARI | QER white paper | our approach |
Related models include QARS (Electronics, 2025) and Rufino et al.'s IEQ (arXiv, 2026).
What QER can and cannot yet claim
- Organise HNDL uncertainty
- Separate timing from severity
- Make evidence and unknown scope visible
- Identify shared dependencies
- Support governed relative comparison
- Claim a validated quantum loss cost
- Set technical premium or capital
- Support binding or portfolio limits
- Automate underwriting decisions
QER is mathematically specified and built to pass structural validation. It has not been empirically validated, because there is no body of HNDL claims to validate against yet. That is the gap a design partner closes.