What Is Q-Day? The Date Quantum Computers Break Classical Encryption

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What Is Q-Day? The Date Quantum Computers Break Classical Encryption

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What Q-Day Means

Q-Day (sometimes Y2Q) is industry shorthand for the moment a Cryptographically Relevant Quantum Computer (CRQC) exists. A CRQC can run Shor's algorithm on real-world cryptographic parameters like RSA-2048 or ECDH P-256. Q-Day is not a fixed date; it is a probability distribution estimated by expert surveys.

Why the Term Is Useful

Q-Day gives non-technical stakeholders a concrete handle for an otherwise abstract threat.…