Err, guess that was more than two points.

Two points. First of all, I’m somewhat confident we’ll learn that a CRQC is imminent with some time left prior to theft being actually possible, see Secondly, I would be surprised, though it’s certainly possible, if a QC is only able to steal coins after a year of constant compute. While they won’t be instant, maintaining coherence for long is one of the key challenges, so compute being longer than minutes to break a key (with some probability, maybe it takes some number of tries, though) seems somewhat unlikely. Finally, its worth pointing out that one of the best ways we have to ensure people retain access to their bitcoin (allowing proof-of-seedphrase to allow for spends) *requires* that we freeze vulnerable spend paths before they can be otherwise stolen. So I think that should weigh pretty heavily in favor of freezing. Of course, however, we cannot decide this for any future community and I think we agree it’s *highly* dependent on the particulars of what public information is available and what the timelines look like. The best we can do is speculate on likely scenarios and then decide what we think should happen in them. Sadly, the freeze-vs-not decision is important today, because it impacts what choices we have available to begin preparing - if freezing is highly likely, we can “hide” QC safety in taproot leaves today without impacting wallets. If it’s not, it has to be a separate address type which has *huge* deployment timeline challenges (there’s *still* exchanges that can’t send to taproot addresses, for example…)

No, you’re confusing the tech details for the reality. if someone steals a private key a court would force them to return the funds, because *obviously* it’s not theirs.

The solution to that concern is lead time :). Provide a way to embed a QC-safe pubkey in outputs today, give wallets plenty of time to adopt it, then there will have been years and years of lead time :)

In the face of a CRQC you cannot. That’s the point. You can in the narrow exception case of having created the key using a seedphrase-based derivation.

Does it? First of all you didn’t engage with the argument in the post at all, so I’d encourage you to do so. But to your point, I disagree. You could also see this as preventing these coins from being stolen. In fact, in order to enable people to claim funds that were stored i but using a seedphrase-based derivation you *have* to freeze i spend paths. Given that is the vast majority of wallets today, I find it hard to believe the tradeoff of screwing most bitcoiners is worth it.

It’s stealing if it’s not yours lol. “Theft” isn’t a technical term, it’s a moral one.

Yes

It sounds like you’re assuming I’m advocating for freezing at any point soon or prior to it being incredibly obvious that a CRQC is a short-term reality and largely unavoidable. I’m not.

(I know, this means I agree with Sailor…weird spot for me too‏)

Certainly possible, yes. I’d be fairly surprised, though. Yes, if a CRQC becomes realistic there may be an incentive to hide it so that you can complete it and go steal a bunch of bitcoin, but generally conspiracies don’t really scale - it seems to me it would be incredibly unlikely that a large team of expert scientists (not to mention investors and executives and support staff) would not be able to keep quite that they’re within shooting distance of a CRQC. More generally, while it’s possible that this happens via some huge breakthrough, that isn’t what we’ve seen so far with QCs - they’ve been very slow deliberate progress iterating in small public steps. A startup making good progress for 5 years then suddenly going dark without shutting down may well also be an indication of something. Ultimately this gets into the “it’s hard to speculate what a future community might do” because there is so much detail to any potential scenario that would go into such a decision. In my (fairly strong) opinion, the community is likely to have enough information to be relatively confident that a CRQC is highly likely at least 1-5 years prior to it existing (where the range is mostly uncertainty about the rate, not uncertainty about the state of things), but it certainly could happen that I’m wrong. Ultimately we can’t decide for the future community, but we do need to at least somewhat predict what they’re going to do because it’s important to understand it to help us decide what to do today to prepare. This all somewhat ignores the possibility that a government gets a CRQC first. I’m admittedly not incredibly concerned about that, both because so far it appears the most advancements have been in private companies willing to throw money at this, but even if that changes, a government leaking that they have a CRQC by stealing Bitcoin doesn’t seem super likely to me either.

Yea, though minor nit: HD doesn’t necessarily mean seedphrase, though I think basically the only modern wallet this applies to is Bitcoin Core.

You have two choices - let a CRQC company steal their coins or freeze them and let those with a seedphrase (which is most modern wallets!) get their money back. It seems really dumb to cut off our nose to spite our face here.

The current QC research world is quite open, and I see little reason to think that that will change any time soon. It’s possible it does, of course, but the companies and scientists working to build them want credit, to attract investment, to attract customers (once they have something useful), etc.

No one is advocating freezing QC-vulnerable spend paths any time soon. And if no CRQC ever appears, then no such freezing should ever occur! The question is only what to do if a CRQC is clearly going to exist within a relatively short time period - do you freeze and let people with seed phrases get their money, or do you let the CRQC operator steal it all?

You’re assuming I’m advocating for doing this now or any time soon, which I very much am not. The only time where it makes sense to consider freezing QC-vulnerable coins is when it’s very obvious that a CRQC is on the immediate horizon and they’re going to be stolen if nothing is done. Yes, we strongly agree that options for QC-secure Bitcoin storage should be provided *long* before that time comes, and without that any discussion of freezing also makes no sense.

I agree it’s not a technical problem, but of course technical details impact the available options and should be considered. Yes, we agree that “preemptively stealing coins because they may theoretically get stolen in the future” is a terrible idea. Considering such a change at any time prior to when it’s clear that a CRQC is on the immediate horizon and clearly going to happen would be absolutely insane. But once you do reach that point, some vulnerable coins are not going to be claimable by their owners no matter what you do. I prefer to allow some of the owners to get their funds back by freezing and enabling claims via a ZK proof of seedphrase over letting some QC startup steal all the coins. Seems kinda obvious that the community would prefer that to me, but I guess maybe not.

You didn’t meaningfully engage with any of my arguments, which is a bit sad, but you know that isn’t going to happen. Any QC startup that gets that far is going to have investors that want paid back. They’ll sell about as quickly as they can.

I believe you missed that disallowing “Quantum Recovery” is required in order to allow a majority of coins to be recovered by their rightful owners! We can allow people to spend funds if they can prove that they were built using a seedphrase and they know the seedphrase, but this only works if vulnerable spend paths are prevented!

Because the supply of Bitcoin available on markets suddenly 10xing impacts everyone.

It’s *way* more than 5%! A CRQC operated by a private entity will almost certainly not be interested in stealing 5% of the supply and sitting on it, they’ll likely want to sell a decent chunk of their stolen coins to pay back investors for the immense R&D cost they spent. The total quantity of coins available on markets is not anywhere close to 20M, it’s a tiny fraction. Having something even like 1-2% of total Bitcoin supply flood the market at once is going to have a very large impact on price. As for your claim that this is somehow changing a fundamental property of Bitcoin, i think you’re losing the Bitcoin philosophy for the way it happened to be written down. Yes, it’s critical for Bitcoin to have a hard line in the sand against coin theft. But you don’t get to pick here - the coins are going to be stolen or frozen no matter what you do. Getting myopic about *who* is doing it isn’t a part of Bitcoin’s value proposition, you’re just reading too much into the way the rules happened to be written down, not the reason for them.