[dibujante]

Yes, I believe so, although millions of qubits are still many orders of magnitude away from the largest quantum computers currently in existence. If Moore's Law applies to quantum computers (big if) then it will take about 50 years for quantum computers to crack 256-bit encryption within a day. Maybe this will spark a cryptography arms race where keys just get larger for a while to postpone that day.

[SAI_Peregrinus]

There also seem to be some fundamental limits on computation in physical systems. The Landauer limit is a famous one. Even with quantum computers, you quickly start needing ridiculous amounts of energy, on the order of "build a dyson swarm". Any symmetric system with a 512-bit key will be secure against solar-system sized quantum computers for many human lifetimes.

[macksd]

The arms race already exists: hash sizes and standard key sizes have increased. Because Moore's Law already applies to classical computers: you effectively lose 1 bit of entropy / security every year.

[upofadown]

I think that would be a bit every 2 years based on Moore's law after the 80's and actual progress has been slower than that for something like a decade now. There are looming fundamental physical limits.

Moore's law refers to hardware capacity and not speed. If you can't figure out how to completely parallelize your attack then that is important. And things are not getting significantly faster.

So a lot of stuff is likely to be safe indefinitely under current technological conditions. A complete breakthrough like quantum computing would be required. Makes it hard to predict things.