IBM quantum computer solves classically intractable problem in 15 minutes

[u/National-Dragonfly35]

https://www.sciencedaily.com/releases/2026/08/260829035219.htm

"The researchers showed that their method preserves the same computational hardness criteria associated with RCS, meaning the problem remains extremely difficult for classical computers. At the same time, the added structure allows errors to be detected during the quantum computation."

[u/Cryptizard]

Yes. A huge point. It is one of the biggest challenges facing the internet and technology landscape in the next decade. If anything it is massively under hyped.

[u/cookie_tech → u/Cryptizard]

I'd argue that PQC (post-quantum cryptography) is slightly over-hyped.

I'm in the cybersecurity world and many well-respected cybersecurity experts believe that we may have a quantum computer that is powerful enough to break quantum computing by 2030.

Meanwhile, I have several colleagues who specialize in the physics side of quantum computing, and (according to them), even with recent breakthroughs, we are still optimistically decades away from a quantum computer that's powerful enough to break RSA.

Do I think it's important to prepare for worst-case scenarios? Sure. But, realistically anything encrypted now that is important enough to be relevant in 30+ years when RSA is finally broken has already been encrypted with PQC.

[u/Cryptizard → u/cookie_tech]

30 years is waaaay too optimistic. You can plot the growth in physical qubits and it is a very steady trend over the past 10 years, with no sign of stopping. That has us reaching Q-day in around 10-15 years.

BUT, most people ignore the fact that we are simultaneously finding more efficient circuits to implement Shor's algorithm. It has gone from 1 billion qubits, to 50 million qubits, to now under one million qubits to run Shor's algorithm on cryptographically relevant inputs.

And that also depends on how efficient error correction is. Right now we are assuming 1000 physical qubits per logical qubit, but since gate fidelities are also increasing steadily, that number could be much lower.

The best circuits we have take only ~800 logical qubits.

https://ecdsa.fail/

So the scaling here is going steadily in three separate axes at once, which all compound, with no signs of stopping in any of them. To take 30 years there would have to be some major unexpected roadblock that nobody is aware of. I wouldn't risk anything important on that bet.

A physicist is not going to know about algorithmic improvements or error correction improvements. They are only looking at one part of the picture.

[u/Foreign_Implement897 → u/Cryptizard]

But what if I want it to stir?