Willow quantum chip demonstrates verifiable quantum advantage on hardware • Hacker News Board

Post by smeej » Fri, Oct 31, 2025, 8:49 PM UTC

andrewla wrote: post #61

bilsbie wrote: post #51

Earlier quoted context omitted.

I don’t see why bitcoin wouldn’t update its software in such a case. The majority of minors just need to agree. But why wouldn’t they if the alternative is going to zero?

How could updating the software possibly make a difference here? If the encryption is cracked, then who is to say who owns which Bitcoin? As soon as I try to transfer any coin that I own, I expose my public key, your "Quantum Computer" cracks it, and you offer a competing transaction with a higher fee to send the Bitcoin to your slush fund. No amount of software fixes can update this. In theory once an attack becomes…

Wouldn't they have to crack the private key by the time the block is mined? Otherwise that transaction would already be sent to another address? I don't have a good idea how long it would take supercomputers to crack a single private key, so I don't know if 13,000x faster would be fast enough, but I don't think it would.

The private key is a 256-bit number. I don't think even 13,000x faster than supercomputers is going to get your cracking time under the time for a 10-minute block. 2^256 is a really, really, really big number.