Ok, so ... what would be required for the 8 bit key? Do we have reputable numbers? And are the qubits in the article equivalent to other qubits or are they lacking in some way?
You need a few dozen logical qubits. Qubits that have negligible errors and do not lose coherence. The problem is that a single logical qubit takes hundreds of physical qubits and advanced error correction techniques to construct.
The more I hear about quantum computing the more it sounds like make believe grift. I first heard about it in a 2600 magazine in 1997 or so. And the claims and "way forward" then and now are roughly equivalent.
Read as: I've heard for nearly 30 years that quantum is just around the corner, and we need post quantum cryptography.
Or, as reverend Sharpton said: "All hell's gunna break loose; and you're gunna need a Bitcoin!"
To be fair the story has been consistent. The hardware is lacking and the predictions are testable given advances in it.
When you compare it to the historical development of classical computers it's proceeding at a decent rate. Imagine if we'd needed hundreds of thousands of transistors before being able to demonstrate actually useful work by a classical computer. They likely never would have been developed in the first place.
Cryptography wise I'd expect dire warnings about any theoretical attack that's reasonably plausible. Better to react immediately than sit around waiting for it to materialize. It took over 15 years after the warnings for SHA to be broken in practice and I don't necessarily expect that SHA2 ever will be but we've moved on to SHA3 nonetheless.
to compare, ENIAC had 18,000 tubes and 1200 relays, and could perform 5000 additions, or 3 square roots per second. in 1956, when it was decommissioned.
that was 80 years ago, for the military. So plotting that out, first actual PC was 25 years after ENIAC was decommissioned, the IBM PC 5150, with 29,000 transistors in the 8088. 12 years later, the 586 had 3.1mm transistors, P4 had 42mm, 10 years later (2003) p4xe had 169mm (but a year earlier there were only 65mm in the p4). haswell, ten years later, 1.4 billion transistors. in 2023, AMD ryzen 7800x3d had 6.5 billion transistors.
Well, i did this a few times between 2011-2016 and predicted SSD/NVME and spindle sizes through this year pretty accurately. Moore's "law" said the graph has a maximum angle, but i think most people think it implies a minimum angle. the graph i plotted is a lot less steep than Moore's law ought to imply, but these are all desktop CPUs - workstation/server CPUs are over 100 billion transistors already and are well within the constraints of Moore's law.
