Are there any real Quantum Computers yet?
https://en.wikipedia.org/wiki/Integer_factorization_records#...
Machines that can would quickly become important to national security though.
The cryptographic implications of QC are absurdly exaggerated.
QC has no practical impact on symmetric (AES, ChaCha) or hash (SHA2, SHA3, Blake) algorithms. Impact is isolated to number-theoretic asymmetric ciphers of certain types (DH, ECDH, ECDSA, EDDSA, etc.) and even there practical attacks would require very large, fast, low-noise quantum computers. The link I posted above is to a project to create the first NIST-certified asymmetric algorithms believed to not be vulnerable to quantum attack, rendering the whole thing pretty much moot.
Every(?) current TLS session is vulnerable. _Many many_ auth sessions of other types are vulnerable. At least petabytes of stored sessions can be decoded (though not all).
It's hard to say how it's exaggerated at all. It's pretty much the device from Sneakers, but real.
That it won't break every possible thing for all time is true, but it's still about as huge as any practical thing can be.
It would require a doubling of key lengths to maintain security against quantum Grover search attacks.
> to create the first NIST-certified asymmetric algorithms believed to not be vulnerable to quantum attack
That will likely lead to much more than a doubling of key sizes; perhaps two orders of magnitude bigger. It will severely impact resource constrained cryptographic devices such as credit card chips.
Grover could in theory reduce a 256-bit cipher like AES-256 or ChaCha to a 128-bit cipher. 128 bits is still far beyond what can be brute forced with any sane or practical amount of resources or time.
It would mean 128-bit keys would be unsafe, but 256-bit or higher has been recommended for years anyway for reasons beyond QC like birthday attacks.
Also keep in mind that this is a theoretical (as in big-O notation) speedup. Real world performance would depend a ton on the speed of the quantum computer. If a QC running Grover's algorithm isn't at least as fast as e.g. a conventional CPU then it might not be much faster in practice than a custom ASIC brute forcing a full strength key. That would make it pretty much an academic demo, not even useful in practice against 128-bit keys.
It's sad that no-one has demonstrated a factorization of 4+4 bits (which should include factorizing 55,65,77,91, and 143). That would be an important milestone I think.
1/ Definition of "real", "quantum" and "computer" may vary.
More seriously I don't think there's a real bar to what constitutes a "real" quantum computer, so it's in the eye of the beholder at this point I think.
As far as I know from publicly available info, there's nothing resembling a practically usable quantum computer yet (as in, a computer that would outperform a conventional one at some practical task).
Gate model computers interest everyone because of the potential to factor large numbers; this could potentially render a lot of existing and past cryptography open to decryption that otherwise will be locked up for aeons, especially considering the apparently decaying effect of Moore's Law of late. However, it probably takes millions or billions of gate qubits to do that, whereas thousands of annealing qubits are enough to solve some interesting problems, and to contribute to finding better solutions when combined with classical compute in a hybrid setup.