Quantum computing bombshells that are not April Fools

(scottaaronson.blog)

76 points | by Strilanc 4 hours ago

6 comments

  • amluto 1 hour ago
    One thing I find rather amazing about all of this is the degree to which the Bitcoin community has tried, for years, to claim that quantum computers will be another other than a complete break.

    Sure, it takes a pretty nice quantum computer or a pretty good algorithm or a degree of malice on the part of miners to break pay-to-script-hash if your wallet has the right properties, but that seems like a pretty weak excuse for the fact that the entire scheme is broken, completely, by QC.

    Does there even exist a credible post-quantum proof protocol that could be used to “rescue” P2SH wallets?

    • Strilanc 25 minutes ago
      The best proposal I have heard for rescuing P2SH wallets after cryptographically relevant quantum computers exist is to require vulnerable wallets to precommit to transactions a day ahead of time. The precommitment doesn't reveal the public key. When the public key must be exposed as part of the actual transaction, an attacker cannot redirect the transaction for at least one day because they don't have a valid precommitment to point to yet.
  • tombert 1 hour ago
    Here's hoping that my stock for D-Wave ends up being worth something.

    Quantum computing seems super cool, but I've been a little skeptical of it actually ever yielding anything useful. I would love to be wrong, it seems neat, and I have read through a few books on the subject and played with simulators, so I'm not completely talking out of my ass here, but quantum as a whole has kind of felt like vaporware to me.

    As I said, I have stock in D-Wave, obviously it would be in my best interest for quantum to end up as cool as it seems.

    • crispyambulance 23 minutes ago
      I got some too. Obviously the principles behind quantum computing are perfectly sound. It's just those pesky engineering obstacles.

      One of the companies around today or in the near future will be the one who makes it work at a practical scale. It will have enormous impact, but I think it will be a slow-burn kind of thing as making effective use of quantum computers will take a long time to evolve, IMHO.

      Unfortunately, Google and IBM are also working on this stuff and they have deep pockets. They might do it, but even if they don't they may very well decide to acquire whoever does.

      These stocks (IONQ, RGTI, QBTS, XNDU) are a sort of thinking-man's LOTTO ticket which will have its numbers called anytime within the next 5 to 20 years (probably closer to 20). I think they're worthwhile to hold in affordable quantities to see what happens. It might hit big, or it might fizzle out for a variety of reasons. There will also be some hype-driven market sugar-rushes along the way that are an opportunity to rake in a modest profit. This has happened already with IONQ, RGTI and QBTS earlier this year. It will certainly happen again when the patagonia-vest people get jazzed about something.

    • esseph 1 hour ago
      You can rent Quantum computing time from IBM cloud today:

      https://www.ibm.com/quantum/products

      https://quantum.cloud.ibm.com/docs/en/guides/plans-overview

      I have NOT used it, but the idea is interesting.

      • AlexCoventry 29 minutes ago
        You can rent it, but it's basically worthless at this stage.
  • ChrisArchitect 1 hour ago
    Related:

    Discussion on the Google one,

    Safeguarding cryptocurrency by disclosing quantum vulnerabilities responsibly

    https://news.ycombinator.com/item?id=47582418

  • GeoSys 42 minutes ago
    So does BTC need to hard fork? Good luck getting to a consensus again ...
  • pmarreck 1 hour ago
    Can quantum computing do even basic math yet? I think this was the holdup. Or perhaps I'm missing the point.
    • GeoSys 43 minutes ago
      It doesn't do basic math ... just the hard one :)
  • socketcluster 46 minutes ago
    Maybe it's a good time to start promoting my 5 year old, lightweight, hand-crafted, battle-tested, quantum-resistant blockchain: https://capitalisk.com/

    It's about 5000 lines of custom code. Crypto signature library written from scratch.

    • EdwardDiego 31 minutes ago
      > Crypto signature library written from scratch.

      That's a sentence every white hat cryptography enthusiast loves to hear lol.