What is Q-Day?
The day a quantum computer can break the public-key encryption in wide use today, such as RSA-2048 or 256-bit elliptic curves.
Nobody knows when it will come. The Q-Day tracker charts every major estimate against the machines built so far. The answer depends on two moving numbers: how many qubits the best attack needs, which has been falling as researchers find better methods, and how many good qubits the largest machines have, which has been rising.
It may not be announced. Whoever builds the first capable machine could keep it quiet, which is one reason governments are setting deadlines to move to post-quantum cryptography by the early to mid 2030s.
Related
- Shor's algorithmA quantum algorithm, published by Peter Shor in 1994, that factors large numbers and breaks the encryption most of the internet uses for key exchange and signatures.
- Harvest now, decrypt laterRecording encrypted data today in order to decrypt it once a capable quantum computer exists.
- Post-quantum cryptographyEncryption that runs on ordinary computers and is designed to resist attacks by quantum computers.
- Logical qubitA reliable qubit built from many physical qubits using error correction.