The Q-Day Red Team — Harvest Now, Decrypt Later

Q-Day is the moment a cryptographically-relevant quantum computer can break today's public-key cryptography — RSA, elliptic curve, the math that protects almost every secret in transit. Nobody knows the year. That uncertainty is the trap. Adversaries don't need Q-Day to have arrived; they only need to bank your encrypted traffic now and wait. The teaching point is Mosca's inequality. Q-Day is not a date. It's an inequality.

Lens A — 2026

The Attacker

An adversary SIGINT collector. Choose which encrypted streams to harvest and bank now, under a finite storage budget. The clock advances to a Q-Day year you don't control. Long-shelf-life secrets are worth stealing today.

Lens B — 2026

The Defender

A federal CISO under the Executive Order deadlines. Allocate scarce migration effort across systems, each with a shelf-life X and a migration time Y. At Q-Day, any system where X + Y exceeded Z is already breached.

Choose a lens and make all three decisions to generate your posture verdict.

Your Posture

Sources & the real clock

This exercise is fiction built on a real policy clock. The targets and systems are illustrative; the standards and deadlines are not.

NIST finalized its first post-quantum cryptography standards in August 2024: FIPS 203 (ML-KEM), FIPS 204 (ML-DSA), and FIPS 205 (SLH-DSA). csrc.nist.gov/projects/post-quantum-cryptography
Executive Order 14412, signed June 22, 2026, directs federal high-value systems to migrate to PQC key establishment by Dec 31, 2030 and PQC signatures by Dec 31, 2031. whitehouse.gov
NSA CNSA 2.0: new national-security systems are expected to support PQC from Jan 1, 2027, with full NSS quantum resistance targeted by 2035.
NSM-10 (2022) and OMB M-23-02 require annual cryptographic inventories of quantum-vulnerable systems — you cannot migrate what you have not inventoried.
Gidney (Google, May 2025, arXiv 2505.15917) estimated RSA-2048 could be broken with under 1 million noisy qubits in under a week — roughly a 20× reduction from his 2019 estimate. The cryptanalytic bar dropped; the hardware bar did not move.
"Harvest now, decrypt later" is treated as a current threat by NSA, CISA, and the FBI.

No specific Q-Day year is presented here as fact. Q-Day timing is uncertain and forecast. The whole point is Mosca's inequality — X + Y > Z — not a predicted date.

All Widgets

The Q-Day Red Team

Harvest Now, Decrypt Later

Q-Day is the moment a quantum computer can break today's public-key crypto. Nobody knows the year — and that's the trap. Q-Day is not a date. It's an inequality: if your secret's shelf-life plus your migration time runs past Q-Day, it's already exposed today.