Willow quantum chip demonstrates verifiable quantum advantage on hardware

Every time I mention quantum computing as a threat to crypto (which I have been for years), I get downvoted to oblivion. I guess we have a lot of HODLers here. A bet on crypto is a bet against quantum computing.

I haven't seen anyone post any progress on factoring large numbers with quantum computers in a while. Annealers won't do it efficiently, but probably still hold the record anyway, for a relatively small number you could do classical hardware. Gate model machines with enough qubits to do it are still ages off. Bitcoin should find a way to transition to a post-quantum algorithm, but that's about it. As long as they do it before anyone has a big enough QPU, they're fine, and nobody is even close, it seems.

I haven't once even thought of investing in crypto, and think that the technology is mostly useless and proof of work schemes should be banned on environmental grounds.

Even so, I don't agree that quantum is a threat to crypto. There are already well known quantum-resistant encryption schemes being deployed live in browsers, today. Crypto can just start adopting one of these schemes today, and we're still probably decades away from a QC that can factor the kinds of primes that crypto security uses. The transition will be slightly more complex for proof of work schemes, since those typically have dedicated hardware - but other types of crypto coins can switch in months, most likely, if they decide to, at least by offering new wallet types or something.

>There are already well known quantum-resistant encryption schemes being deployed live in browsers, today. Crypto can just start adopting one of these schemes today, and we're still probably decades away from a QC that can factor the kinds of primes that crypto security uses.

It's very strange that some people act like switching over to a post quantum cryptography scheme is trivial. Did you watch the video I replied to, which is a talk by an actual quantum computing researcher?

Unless advances in QC could rewrite the blockchain then there's not much to worry about. If the crypto algorithms are compromised, you coins are pretty much frozen on the chain until a new algorithms are implemented. Are you're arguing QC makes signatures/verification/mining impossible?

Why though? Who is to decide which point of the blockchain is the good one and which blocks to “reject”?

Think twice. Everyone who hosts the blockchain would decide to stop because he invested in crypto, at least with some hardware costs. Beside of the small group of people that owns a quantum computer. I don't expect that this group is >50% of the people that hosts the blockchain.

You don't need >50% of bad actors to compromise the blockchain, but rather >50% of the total hashing power. This could very well be achievable by a small group of people with QC at some point.

How does QC aid SHA256 hash throughput?