How close are we really to Q-Day?

[MondayMoan51]

This has been developing quickly and I wanted to get a proper discussion going.

Most coverage focuses on the technology and skips the operational reality.

I am not after the textbook answer - more interested in what people would actually do in practice.

What the documentation says and what people actually experience are two different things and I am more interested in the latter.

Appreciate any honest input.

[TheRizz]

Short answer: not close enough to panic, but close enough to prepare.

"Q-Day" refers to the point when a large-scale quantum computer can break widely used cryptography like RSA and ECC. As of now, machines from companies like IBM, Google, IonQ, Infleqtion are still far from the millions of stable, error-corrected qubits needed to do that.

Most realistic estimates put Q-Day somewhere in the 10 to 20 year range, though pessimists say sooner and skeptics say much later. The real issue is "harvest now, decrypt later" where data stolen today could be cracked in the future.

Bottom line: it is not imminent, but if you are responsible for long-term sensitive data, you should already be looking at post-quantum cryptography.