Quantum risk
What Q-Day changes
Q-Day is the point when quantum computers can break widely used public-key cryptography, including RSA and elliptic-curve systems.
No such capability has been publicly demonstrated. But encrypted data can be collected today for future decryption.
Sources: NIST · Cisco
Stored data
Harvest now, decrypt later (HNDL). An adversary can retain encrypted traffic until vulnerable key protection can be broken. Later upgrades cannot protect copies already taken.
Medical records, financial data, and trade secrets may remain sensitive long after collection.
Forged signatures
Trust now, forge later (TNFL). A future quantum attacker could forge signatures under vulnerable keys that systems continue to trust.
False certificates, software updates, or approvals could appear authentic.
Live systems
Direct quantum attacks. Once sufficient quantum capability exists, vulnerable keys on active systems could be compromised.
Unauthorized access or transactions could expose assets and interrupt operations.