Quote from: jackg on September 24, 2019, 10:20:44 PM

I thought it broke at a complexity of 128^3 from what was previously discussed last time (I have no links though). Isn't this old news? I'm sure we saw the same headline about 6 months ago...

Forbes and the financial Times seem really awful sources nowadays, perhaps their editor bought stocks in Google or something..., There seemed to be a consensus that the sha256 hashing algorithm was quantum proof too - people don't want to act until the nsa release standards of quantum proof encryption so we're stuck in the hope that's the case anyway...

Sorry if I understood wrongly, but:
Did you mean complexity of 2^128, as that is the complexity of cracking bitcoin with the best known non QC algorithm. And QC could not use that algorithm, so it would probably need the full 256 qubits to do the calculations.

As adding more qubits to a QC gets exponentially harder, I do not believe we will see a true 256 qubit QC for a long looong time, if ever.

According to what I have read about the subject, sha256 is not vulnerable to quantum computers.

There are many people, who do not trust NSA any longer, so I wouldn't be so sure that bitcoin would move to their quantum "proof" standard when they publish one