Explication
Qu'est-ce que le Q-Day et pourquoi devriez-vous vous en préoccuper ?
Le Q-Day désigne le moment où un ordinateur quantique devient suffisamment puissant pour casser le chiffrement RSA — la base de la sécurité internet actuelle.
Technologie
Cryptographie post-quantique : la course pour protéger Internet
Le NIST a finalisé ses premiers standards de chiffrement post-quantique. Mais à quelle vitesse le monde les adoptera-t-il — et est-ce suffisamment rapide ?
Recherche
La puce Willow de Google : une étape vers le Q-Day
Le dernier processeur quantique de Google change la donne. Nous décryptons ce que la percée Willow signifie réellement pour le calendrier du Q-Day.
Standards & Politique
Le NIST sélectionne HQC : un bouclier de secours contre les attaques quantiques
En mars 2025, le NIST a choisi HQC comme cinquième algorithme post-quantique — un filet de sécurité basé sur des mathématiques entièrement différentes.
What is Q-Day?
Q-Day is the predicted moment when a quantum computer becomes powerful enough to break RSA encryption — the system protecting most internet traffic, banking, and communications today. When it arrives, any data encrypted with current standards can be decrypted retroactively.
When will it happen?
Estimates vary: Google's internal security team targets 2029, NIST and the NSA are planning for 2030 as a critical migration deadline, and the Global Risk Institute puts a 50% probability on 2035. The timeline depends heavily on progress in qubit quality and error correction.
Am I already at risk?
"Harvest now, decrypt later" attacks are already happening — state actors are collecting encrypted data today to decrypt once a capable quantum computer exists. Sensitive data with long shelf-life (medical records, financial history, state secrets) is most at risk.
What is post-quantum cryptography?
Post-quantum cryptography (PQC) refers to cryptographic algorithms designed to be secure against quantum attacks. In 2024, NIST published the world's first PQC standards — CRYSTALS-Kyber and CRYSTALS-Dilithium — to replace vulnerable RSA and ECC encryption.
What can I do?
If you run critical infrastructure or handle sensitive long-lived data: begin a cryptographic inventory, follow NIST's migration guidance, and start transitioning to PQC-ready systems. Most major cloud providers are already offering PQC-compatible TLS options.
Will Bitcoin and crypto survive Q-Day?
Most cryptocurrencies use elliptic curve cryptography (ECC) for wallets — which is vulnerable to quantum attacks. Bitcoin's ECDSA signatures could be broken by a sufficiently large quantum computer. The crypto community is actively discussing post-quantum migration paths.
défiler →
We are already having the wrong conversation in cryptography if we argue about whether we have one, three, or five years before quantum computers will break today's security algorithms. We must always be ahead of the curve — especially in the era of 'Store now, decrypt later'.
In three to five years' time, we will have that moment where from a cryptographic standpoint we have to adapt to quantum, for sure.
Preparing for a post-quantum world will be a complex change programme that makes fixing the Millennium Bug look easy.
The averaged expert estimate of the probability of a cryptographically relevant quantum computer emerging within the next 10 years is now between 28% and 49% — the highest in this report's history.
Q-Day could come as soon as 2025. The question is not if, but when — and most organisations are dangerously unprepared.
Elliptic curves are going to die. There is about a 20% chance that quantum computers capable of breaking today's cryptography arrive before 2030 — and that is not a risk Ethereum can afford to ignore.
It's a really serious threat, and I think the modern crypto community doesn't fully understand just how serious it is. My forecast is a matter of years — not decades.
When a suitably powerful quantum computer becomes available, conventional digital signature schemes will be broken — and all existing ledgers will be susceptible to attack. I built QRL because this is not a theoretical problem.