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From: Agustin Cruz <agustin.cruz@gmail.com>
Date: Mon, 24 Mar 2025 08:19:30 -0300
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Subject: Re: [bitcoindev] Against Allowing Quantum Recovery of Bitcoin
To: AstroTown <saulo@astrotown.de>
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I=E2=80=99m against letting quantum computers scoop up funds from addresses=
 that
don=E2=80=99t upgrade to quantum-resistant.
Saulo=E2=80=99s idea of a free-market approach, leaving old coins up for gr=
abs if
people don=E2=80=99t move them, sounds fair at first. Let luck decide, righ=
t? But I
worry it=E2=80=99d turn into a mess. If quantum machines start cracking key=
s and
snagging coins, it=E2=80=99s not just lost Satoshi-era stuff at risk. Plent=
y of
active wallets, like those on the rich list Jameson mentioned, could get
hit too. Imagine millions of BTC flooding the market. Prices tank, trust in
Bitcoin takes a dive, and we all feel the pain. Freezing those vulnerable
funds keeps that chaos in check.
Plus, =E2=80=9Cyour keys, your coins=E2=80=9D is Bitcoin=E2=80=99s heart. I=
f quantum tech can steal
from you just because you didn=E2=80=99t upgrade fast enough, that promise =
feels
shaky. Freezing funds after a heads-up period (say, four years) protects
that idea better than letting tech giants or rogue states play vampire with
our network. It also nudges people to get their act together and move to
safer addresses, which strengthens Bitcoin long-term.
Saulo=E2=80=99s right that freezing coins could confuse folks or spark a sp=
lit like
Ethereum Classic. But I=E2=80=99d argue quantum theft would look worse. Bit=
coin
would seem broken, not just strict. A clear plan and enough time to migrate
could smooth things over. History=E2=80=99s on our side too. Bitcoin=E2=80=
=99s fixed bugs
before, like SegWit. This feels like that, not a bailout.
So yeah, I=E2=80=99d rather see vulnerable coins locked than handed to whoe=
ver
builds the first quantum rig. It=E2=80=99s less about coddling people and m=
ore
about keeping Bitcoin solid for everyone. What do you all think?
Cheers,
Agust=C3=ADn


On Sun, Mar 23, 2025 at 10:29=E2=80=AFPM AstroTown <saulo@astrotown.de> wro=
te:

> I believe that having some entity announce the decision to freeze old
> UTXOs would be more damaging to Bitcoin=E2=80=99s image (and its value) t=
han having
> them gathered by QC. This would create another version of Bitcoin, simila=
r
> to Ethereum Classic, causing confusion in the market.
>
> It would be better to simply implement the possibility of moving funds to
> a PQC address without a deadline, allowing those who fail to do so to rel=
y
> on luck to avoid having their coins stolen. Most coins would be migrated =
to
> PQC anyway, and in most cases, only the lost ones would remain vulnerable=
.
> This is the free-market way to solve problems without imposing rules on
> everyone.
>
> Saulo Fonseca
>
>
> On 16. Mar 2025, at 15:15, Jameson Lopp <jameson.lopp@gmail.com> wrote:
>
> The quantum computing debate is heating up. There are many controversial
> aspects to this debate, including whether or not quantum computers will
> ever actually become a practical threat.
>
> I won't tread into the unanswerable question of how worried we should be
> about quantum computers. I think it's far from a crisis, but given the
> difficulty in changing Bitcoin it's worth starting to seriously discuss.
> Today I wish to focus on a philosophical quandary related to one of the
> decisions that would need to be made if and when we implement a quantum
> safe signature scheme.
>
> Several Scenarios
> Because this essay will reference game theory a fair amount, and there ar=
e
> many variables at play that could change the nature of the game, I think
> it's important to clarify the possible scenarios up front.
>
> 1. Quantum computing never materializes, never becomes a threat, and thus
> everything discussed in this essay is moot.
> 2. A quantum computing threat materializes suddenly and Bitcoin does not
> have quantum safe signatures as part of the protocol. In this scenario it
> would likely make the points below moot because Bitcoin would be
> fundamentally broken and it would take far too long to upgrade the
> protocol, wallet software, and migrate user funds in order to restore
> confidence in the network.
> 3. Quantum computing advances slowly enough that we come to consensus
> about how to upgrade Bitcoin and post quantum security has been minimally
> adopted by the time an attacker appears.
> 4. Quantum computing advances slowly enough that we come to consensus
> about how to upgrade Bitcoin and post quantum security has been highly
> adopted by the time an attacker appears.
>
> For the purposes of this post, I'm envisioning being in situation 3 or 4.
>
> To Freeze or not to Freeze?
> I've started seeing more people weighing in on what is likely the most
> contentious aspect of how a quantum resistance upgrade should be handled =
in
> terms of migrating user funds. Should quantum vulnerable funds be left op=
en
> to be swept by anyone with a sufficiently powerful quantum computer OR
> should they be permanently locked?
>
> "I don't see why old coins should be confiscated. The better option is to
>> let those with quantum computers free up old coins. While this might hav=
e
>> an inflationary impact on bitcoin's price, to use a turn of phrase, the
>> inflation is transitory. Those with low time preference should support
>> returning lost coins to circulation."
>
> - Hunter Beast
>
>
> On the other hand:
>
> "Of course they have to be confiscated. If and when (and that's a big if)
>> the existence of a cryptography-breaking QC becomes a credible threat, t=
he
>> Bitcoin ecosystem has no other option than softforking out the ability t=
o
>> spend from signature schemes (including ECDSA and BIP340) that are
>> vulnerable to QCs. The alternative is that millions of BTC become
>> vulnerable to theft; I cannot see how the currency can maintain any valu=
e
>> at all in such a setting. And this affects everyone; even those which
>> diligently moved their coins to PQC-protected schemes."
>> - Pieter Wuille
>
>
> I don't think "confiscation" is the most precise term to use, as the fund=
s
> are not being seized and reassigned. Rather, what we're really discussing
> would be better described as "burning" - placing the funds *out of reach
> of everyone*.
>
> Not freezing user funds is one of Bitcoin's inviolable properties.
> However, if quantum computing becomes a threat to Bitcoin's elliptic curv=
e
> cryptography, *an inviolable property of Bitcoin will be violated one way
> or another*.
>
> Fundamental Properties at Risk
> 5 years ago I attempted to comprehensively categorize all of Bitcoin's
> fundamental properties that give it value.
> https://nakamoto.com/what-are-the-key-properties-of-bitcoin/
>
> The particular properties in play with regard to this issue seem to be:
>
> *Censorship Resistance* - No one should have the power to prevent others
> from using their bitcoin or interacting with the network.
>
> *Forward Compatibility* - changing the rules such that certain valid
> transactions become invalid could undermine confidence in the protocol.
>
> *Conservatism* - Users should not be expected to be highly responsive to
> system issues.
>
> As a result of the above principles, we have developed a strong meme
> (kudos to Andreas Antonopoulos) that goes as follows:
>
> Not your keys, not your coins.
>
>
> I posit that the corollary to this principle is:
>
> Your keys, only your coins.
>
>
> A quantum capable entity breaks the corollary of this foundational
> principle. We secure our bitcoin with the mathematical probabilities
> related to extremely large random numbers. Your funds are only secure
> because truly random large numbers should not be guessable or discoverabl=
e
> by anyone else in the world.
>
> This is the principle behind the motto *vires in numeris* - strength in
> numbers. In a world with quantum enabled adversaries, this principle is
> null and void for many types of cryptography, including the elliptic curv=
e
> digital signatures used in Bitcoin.
>
> Who is at Risk?
> There has long been a narrative that Satoshi's coins and others from the
> Satoshi era of P2PK locking scripts that exposed the public key directly =
on
> the blockchain will be those that get scooped up by a quantum "miner." Bu=
t
> unfortunately it's not that simple. If I had a powerful quantum computer,
> which coins would I target? I'd go to the Bitcoin rich list and find the
> wallets that have exposed their public keys due to re-using addresses tha=
t
> have previously been spent from. You can easily find them at
> https://bitinfocharts.com/top-100-richest-bitcoin-addresses.html
>
> Note that a few of these wallets, like Bitfinex / Kraken / Tether, would
> be slightly harder to crack because they are multisig wallets. So a quant=
um
> attacker would need to reverse engineer 2 keys for Kraken or 3 for Bitfin=
ex
> / Tether in order to spend funds. But many are single signature.
>
> Point being, it's not only the really old lost BTC that are at risk to a
> quantum enabled adversary, at least at time of writing. If we add a quant=
um
> safe signature scheme, we should expect those wallets to be some of the
> first to upgrade given their incentives.
>
> The Ethical Dilemma: Quantifying Harm
> Which decision results in the most harm?
>
> By making quantum vulnerable funds unspendable we potentially harm some
> Bitcoin users who were not paying attention and neglected to migrate thei=
r
> funds to a quantum safe locking script. This violates the "conservativism=
"
> principle stated earlier. On the flip side, we prevent those funds plus f=
ar
> more lost funds from falling into the hands of the few privileged folks w=
ho
> gain early access to quantum computers.
>
> By leaving quantum vulnerable funds available to spend, the same set of
> users who would otherwise have funds frozen are likely to see them stolen=
.
> And many early adopters who lost their keys will eventually see their
> unreachable funds scooped up by a quantum enabled adversary.
>
> Imagine, for example, being James Howells, who accidentally threw away a
> hard drive with 8,000 BTC on it, currently worth over $600M USD. He has
> spent a decade trying to retrieve it from the landfill where he knows it'=
s
> buried, but can't get permission to excavate. I suspect that, given the
> choice, he'd prefer those funds be permanently frozen rather than fall in=
to
> someone else's possession - I know I would.
>
> Allowing a quantum computer to access lost funds doesn't make those users
> any worse off than they were before, however it *would*have a negative
> impact upon everyone who is currently holding bitcoin.
>
> It's prudent to expect significant economic disruption if large amounts o=
f
> coins fall into new hands. Since a quantum computer is going to have a
> massive up front cost, expect those behind it to desire to recoup their
> investment. We also know from experience that when someone suddenly finds
> themselves in possession of 9+ figures worth of highly liquid assets, the=
y
> tend to diversify into other things by selling.
>
> Allowing quantum recovery of bitcoin is *tantamount to wealth
> redistribution*. What we'd be allowing is for bitcoin to be redistributed
> from those who are ignorant of quantum computers to those who have won th=
e
> technological race to acquire quantum computers. It's hard to see a brigh=
t
> side to that scenario.
>
> Is Quantum Recovery Good for Anyone?
>
> Does quantum recovery HELP anyone? I've yet to come across an argument
> that it's a net positive in any way. It certainly doesn't add any securit=
y
> to the network. If anything, it greatly decreases the security of the
> network by allowing funds to be claimed by those who did not earn them.
>
> But wait, you may be thinking, wouldn't quantum "miners" have earned thei=
r
> coins by all the work and resources invested in building a quantum
> computer? I suppose, in the same sense that a burglar earns their spoils =
by
> the resources they invest into surveilling targets and learning the skill=
s
> needed to break into buildings. What I say "earned" I mean through
> productive mutual trade.
>
> For example:
>
> * Investors earn BTC by trading for other currencies.
> * Merchants earn BTC by trading for goods and services.
> * Miners earn BTC by trading thermodynamic security.
> * Quantum miners don't trade anything, they are vampires feeding upon the
> system.
>
> There's no reason to believe that allowing quantum adversaries to recover
> vulnerable bitcoin will be of benefit to anyone other than the select few
> organizations that win the technological arms race to build the first suc=
h
> computers. Probably nation states and/or the top few largest tech compani=
es.
>
> One could certainly hope that an organization with quantum supremacy is
> benevolent and acts in a "white hat" manner to return lost coins to their
> owners, but that's incredibly optimistic and foolish to rely upon. Such a
> situation creates an insurmountable ethical dilemma of only recovering lo=
st
> bitcoin rather than currently owned bitcoin. There's no way to precisely
> differentiate between the two; anyone can claim to have lost their bitcoi=
n
> but if they have lost their keys then proving they ever had the keys
> becomes rather difficult. I imagine that any such white hat recovery
> efforts would have to rely upon attestations from trusted third parties
> like exchanges.
>
> Even if the first actor with quantum supremacy is benevolent, we must
> assume the technology could fall into adversarial hands and thus think
> adversarially about the potential worst case outcomes. Imagine, for
> example, that North Korea continues scooping up billions of dollars from
> hacking crypto exchanges and decides to invest some of those proceeds int=
o
> building a quantum computer for the biggest payday ever...
>
> Downsides to Allowing Quantum Recovery
> Let's think through an exhaustive list of pros and cons for allowing or
> preventing the seizure of funds by a quantum adversary.
>
> Historical Precedent
> Previous protocol vulnerabilities weren=E2=80=99t celebrated as "fair gam=
e" but
> rather were treated as failures to be remediated. Treating quantum theft
> differently risks rewriting Bitcoin=E2=80=99s history as a free-for-all r=
ather than
> a system that seeks to protect its users.
>
> Violation of Property Rights
> Allowing a quantum adversary to take control of funds undermines the
> fundamental principle of cryptocurrency - if you keep your keys in your
> possession, only you should be able to access your money. Bitcoin is buil=
t
> on the idea that private keys secure an individual=E2=80=99s assets, and
> unauthorized access (even via advanced tech) is theft, not a legitimate
> transfer.
>
> Erosion of Trust in Bitcoin
> If quantum attackers can exploit vulnerable addresses, confidence in
> Bitcoin as a secure store of value would collapse. Users and investors re=
ly
> on cryptographic integrity, and widespread theft could drive adoption awa=
y
> from Bitcoin, destabilizing its ecosystem.
>
> This is essentially the counterpoint to claiming the burning of vulnerabl=
e
> funds is a violation of property rights. While some will certainly see it
> as such, others will find the apathy toward stopping quantum theft to be
> similarly concerning.
>
> Unfair Advantage
> Quantum attackers, likely equipped with rare and expensive technology,
> would have an unjust edge over regular users who lack access to such tool=
s.
> This creates an inequitable system where only the technologically elite c=
an
> exploit others, contradicting Bitcoin=E2=80=99s ethos of decentralized po=
wer.
>
> Bitcoin is designed to create an asymmetric advantage for DEFENDING one's
> wealth. It's supposed to be impractically expensive for attackers to crac=
k
> the entropy and cryptography protecting one's coins. But now we find
> ourselves discussing a situation where this asymmetric advantage is
> compromised in favor of a specific class of attackers.
>
> Economic Disruption
> Large-scale theft from vulnerable addresses could crash Bitcoin=E2=80=99s=
 price as
> quantum recovered funds are dumped on exchanges. This would harm all
> holders, not just those directly targeted, leading to broader financial
> chaos in the markets.
>
> Moral Responsibility
> Permitting theft via quantum computing sets a precedent that technologica=
l
> superiority justifies unethical behavior. This is essentially taking a
> "code is law" stance in which we refuse to admit that both code and laws
> can be modified to adapt to previously unforeseen situations.
>
> Burning of coins can certainly be considered a form of theft, thus I thin=
k
> it's worth differentiating the two different thefts being discussed:
>
> 1. self-enriching & likely malicious
> 2. harm prevention & not necessarily malicious
>
> Both options lack the consent of the party whose coins are being burnt or
> transferred, thus I think the simple argument that theft is immoral becom=
es
> a wash and it's important to drill down into the details of each.
>
> Incentives Drive Security
> I can tell you from a decade of working in Bitcoin security - the average
> user is lazy and is a procrastinator. If Bitcoiners are given a "drop dea=
d
> date" after which they know vulnerable funds will be burned, this pressur=
e
> accelerates the adoption of post-quantum cryptography and strengthens
> Bitcoin long-term. Allowing vulnerable users to delay upgrading
> indefinitely will result in more laggards, leaving the network more expos=
ed
> when quantum tech becomes available.
>
> Steel Manning
> Clearly this is a complex and controversial topic, thus it's worth
> thinking through the opposing arguments.
>
> Protecting Property Rights
> Allowing quantum computers to take vulnerable bitcoin could potentially b=
e
> spun as a hard money narrative - we care so greatly about not violating
> someone's access to their coins that we allow them to be stolen!
>
> But I think the flip side to the property rights narrative is that burnin=
g
> vulnerable coins prevents said property from falling into undeserving
> hands. If the entire Bitcoin ecosystem just stands around and allows
> quantum adversaries to claim funds that rightfully belong to other users,
> is that really a "win" in the "protecting property rights" category? It
> feels more like apathy to me.
>
> As such, I think the "protecting property rights" argument is a wash.
>
> Quantum Computers Won't Attack Bitcoin
> There is a great deal of skepticism that sufficiently powerful quantum
> computers will ever exist, so we shouldn't bother preparing for a
> non-existent threat. Others have argued that even if such a computer was
> built, a quantum attacker would not go after bitcoin because they wouldn'=
t
> want to reveal their hand by doing so, and would instead attack other
> infrastructure.
>
> It's quite difficult to quantify exactly how valuable attacking other
> infrastructure would be. It also really depends upon when an entity gains
> quantum supremacy and thus if by that time most of the world's systems ha=
ve
> already been upgraded. While I think you could argue that certain entitie=
s
> gaining quantum capability might not attack Bitcoin, it would only delay
> the inevitable - eventually somebody will achieve the capability who
> decides to use it for such an attack.
>
> Quantum Attackers Would Only Steal Small Amounts
> Some have argued that even if a quantum attacker targeted bitcoin, they'd
> only go after old, likely lost P2PK outputs so as to not arouse suspicion
> and cause a market panic.
>
> I'm not so sure about that; why go after 50 BTC at a time when you could
> take 250,000 BTC with the same effort as 50 BTC? This is a classic "zero
> day exploit" game theory in which an attacker knows they have a limited
> amount of time before someone else discovers the exploit and either
> benefits from it or patches it. Take, for example, the recent ByBit attac=
k
> - the highest value crypto hack of all time. Lazarus Group had compromise=
d
> the Safe wallet front end JavaScript app and they could have simply had i=
t
> reassign ownership of everyone's Safe wallets as they were interacting wi=
th
> their wallet. But instead they chose to only specifically target ByBit's
> wallet with $1.5 billion in it because they wanted to maximize their
> extractable value. If Lazarus had started stealing from every wallet, the=
y
> would have been discovered quickly and the Safe web app would likely have
> been patched well before any billion dollar wallets executed the maliciou=
s
> code.
>
> I think the "only stealing small amounts" argument is strongest for
> Situation #2 described earlier, where a quantum attacker arrives before
> quantum safe cryptography has been deployed across the Bitcoin ecosystem.
> Because if it became clear that Bitcoin's cryptography was broken AND the=
re
> was nowhere safe for vulnerable users to migrate, the only logical option
> would be for everyone to liquidate their bitcoin as quickly as possible. =
As
> such, I don't think it applies as strongly for situations in which we hav=
e
> a migration path available.
>
> The 21 Million Coin Supply Should be in Circulation
> Some folks are arguing that it's important for the "circulating /
> spendable" supply to be as close to 21M as possible and that having a
> significant portion of the supply out of circulation is somehow undesirab=
le.
>
> While the "21M BTC" attribute is a strong memetic narrative, I don't thin=
k
> anyone has ever expected that it would all be in circulation. It has alwa=
ys
> been understood that many coins will be lost, and that's actually part of
> the game theory of owning bitcoin!
>
> And remember, the 21M number in and of itself is not a particularly
> important detail - it's not even mentioned in the whitepaper. What's
> important is that the supply is well known and not subject to change.
>
> Self-Sovereignty and Personal Responsibility
> Bitcoin=E2=80=99s design empowers individuals to control their own wealth=
, free
> from centralized intervention. This freedom comes with the burden of
> securing one's private keys. If quantum computing can break obsolete
> cryptography, the fault lies with users who didn't move their funds to
> quantum safe locking scripts. Expecting the network to shield users from
> their own negligence undermines the principle that you, and not a third
> party, are accountable for your assets.
>
> I think this is generally a fair point that "the community" doesn't owe
> you anything in terms of helping you. I think that we do, however, need t=
o
> consider the incentives and game theory in play with regard to quantum sa=
fe
> Bitcoiners vs quantum vulnerable Bitcoiners. More on that later.
>
> Code is Law
> Bitcoin operates on transparent, immutable rules embedded in its protocol=
.
> If a quantum attacker uses superior technology to derive private keys fro=
m
> public keys, they=E2=80=99re not "hacking" the system - they're simply fo=
llowing
> what's mathematically permissible within the current code. Altering the
> protocol to stop this introduces subjective human intervention, which
> clashes with the objective, deterministic nature of blockchain.
>
> While I tend to agree that code is law, one of the entire points of laws
> is that they can be amended to improve their efficacy in reducing harm.
> Leaning on this point seems more like a pro-ossification stance that it's
> better to do nothing and allow harm to occur rather than take action to
> stop an attack that was foreseen far in advance.
>
> Technological Evolution as a Feature, Not a Bug
> It's well known that cryptography tends to weaken over time and eventuall=
y
> break. Quantum computing is just the next step in this progression. Users
> who fail to adapt (e.g., by adopting quantum-resistant wallets when
> available) are akin to those who ignored technological advancements like
> multisig or hardware wallets. Allowing quantum theft incentivizes
> innovation and keeps Bitcoin=E2=80=99s ecosystem dynamic, punishing compl=
acency
> while rewarding vigilance.
>
> Market Signals Drive Security
> If quantum attackers start stealing funds, it sends a clear signal to the
> market: upgrade your security or lose everything. This pressure accelerat=
es
> the adoption of post-quantum cryptography and strengthens Bitcoin
> long-term. Coddling vulnerable users delays this necessary evolution,
> potentially leaving the network more exposed when quantum tech becomes
> widely accessible. Theft is a brutal but effective teacher.
>
> Centralized Blacklisting Power
> Burning vulnerable funds requires centralized decision-making - a soft
> fork to invalidate certain transactions. This sets a dangerous precedent
> for future interventions, eroding Bitcoin=E2=80=99s decentralization. If =
quantum
> theft is blocked, what=E2=80=99s next - reversing exchange hacks? The sys=
tem must
> remain neutral, even if it means some lose out.
>
> I think this could be a potential slippery slope if the proposal was to
> only burn specific addresses. Rather, I'd expect a neutral proposal to bu=
rn
> all funds in locking script types that are known to be quantum vulnerable=
.
> Thus, we could eliminate any subjectivity from the code.
>
> Fairness in Competition
> Quantum attackers aren't cheating; they're using publicly available
> physics and math. Anyone with the resources and foresight can build or
> access quantum tech, just as anyone could mine Bitcoin in 2009 with a CPU=
.
> Early adopters took risks and reaped rewards; quantum innovators are doin=
g
> the same. Calling it =E2=80=9Cunfair=E2=80=9D ignores that Bitcoin has ne=
ver promised
> equality of outcome - only equality of opportunity within its rules.
>
> I find this argument to be a mischaracterization because we're not talkin=
g
> about CPUs. This is more akin to talking about ASICs, except each ASIC
> costs millions if not billions of dollars. This is out of reach from all
> but the wealthiest organizations.
>
> Economic Resilience
> Bitcoin has weathered thefts before (MTGOX, Bitfinex, FTX, etc) and
> emerged stronger. The market can absorb quantum losses, with unaffected
> users continuing to hold and new entrants buying in at lower prices. Fear
> of economic collapse overestimates the impact - the network=E2=80=99s ant=
ifragility
> thrives on such challenges.
>
> This is a big grey area because we don't know when a quantum computer wil=
l
> come online and we don't know how quickly said computers would be able to
> steal bitcoin. If, for example, the first generation of sufficiently
> powerful quantum computers were stealing less volume than the current blo=
ck
> reward then of course it will have minimal economic impact. But if they'r=
e
> taking thousands of BTC per day and bringing them back into circulation,
> there will likely be a noticeable market impact as it absorbs the new
> supply.
>
> This is where the circumstances will really matter. If a quantum attacker
> appears AFTER the Bitcoin protocol has been upgraded to support quantum
> resistant cryptography then we should expect the most valuable active
> wallets will have upgraded and the juiciest target would be the 31,000 BT=
C
> in the address 12ib7dApVFvg82TXKycWBNpN8kFyiAN1dr which has been dormant
> since 2010. In general I'd expect that the amount of BTC re-entering the
> circulating supply would look somewhat similar to the mining emission
> curve: volume would start off very high as the most valuable addresses ar=
e
> drained and then it would fall off as quantum computers went down the lis=
t
> targeting addresses with less and less BTC.
>
> Why is economic impact a factor worth considering? Miners and businesses
> in general. More coins being liquidated will push down the price, which
> will negatively impact miner revenue. Similarly, I can attest from workin=
g
> in the industry for a decade, that lower prices result in less demand fro=
m
> businesses across the entire industry. As such, burning quantum vulnerabl=
e
> bitcoin is good for the entire industry.
>
> Practicality & Neutrality of Non-Intervention
> There=E2=80=99s no reliable way to distinguish =E2=80=9Ctheft=E2=80=9D fr=
om legitimate "white hat"
> key recovery. If someone loses their private key and a quantum computer
> recovers it, is that stealing or reclaiming? Policing quantum actions
> requires invasive assumptions about intent, which Bitcoin=E2=80=99s trust=
less
> design can=E2=80=99t accommodate. Letting the chips fall where they may a=
voids this
> mess.
>
> Philosophical Purity
> Bitcoin rejects bailouts. It=E2=80=99s a cold, hard system where outcomes=
 reflect
> preparation and skill, not sentimentality. If quantum computing upends th=
e
> game, that=E2=80=99s the point - Bitcoin isn=E2=80=99t meant to be safe o=
r fair in a
> nanny-state sense; it=E2=80=99s meant to be free. Users who lose funds to=
 quantum
> attacks are casualties of liberty and their own ignorance, not victims of
> injustice.
>
> Bitcoin's DAO Moment
> This situation has some similarities to The DAO hack of an Ethereum smart
> contract in 2016, which resulted in a fork to stop the attacker and retur=
n
> funds to their original owners. The game theory is similar because it's a
> situation where a threat is known but there's some period of time before
> the attacker can actually execute the theft. As such, there's time to
> mitigate the attack by changing the protocol.
>
> It also created a schism in the community around the true meaning of "cod=
e
> is law," resulting in Ethereum Classic, which decided to allow the attack=
er
> to retain control of the stolen funds.
>
> A soft fork to burn vulnerable bitcoin could certainly result in a hard
> fork if there are enough miners who reject the soft fork and continue
> including transactions.
>
> Incentives Matter
> We can wax philosophical until the cows come home, but what are the actua=
l
> incentives for existing Bitcoin holders regarding this decision?
>
> "Lost coins only make everyone else's coins worth slightly more. Think of
>> it as a donation to everyone." - Satoshi Nakamoto
>
>
> If true, the corollary is:
>
> "Quantum recovered coins only make everyone else's coins worth less. Thin=
k
>> of it as a theft from everyone." - Jameson Lopp
>
>
> Thus, assuming we get to a point where quantum resistant signatures are
> supported within the Bitcoin protocol, what's the incentive to let
> vulnerable coins remain spendable?
>
> * It's not good for the actual owners of those coins. It disincentivizes
> owners from upgrading until perhaps it's too late.
> * It's not good for the more attentive / responsible owners of coins who
> have quantum secured their stash. Allowing the circulating supply to
> balloon will assuredly reduce the purchasing power of all bitcoin holders=
.
>
> Forking Game Theory
> From a game theory point of view, I see this as incentivizing users to
> upgrade their wallets. If you disagree with the burning of vulnerable
> coins, all you have to do is move your funds to a quantum safe signature
> scheme. Point being, I don't see there being an economic majority (or eve=
n
> more than a tiny minority) of users who would fight such a soft fork. Why
> expend significant resources fighting a fork when you can just move your
> coins to a new address?
>
> Remember that blocking spending of certain classes of locking scripts is =
a
> tightening of the rules - a soft fork. As such, it can be meaningfully
> enacted and enforced by a mere majority of hashpower. If miners generally
> agree that it's in their best interest to burn vulnerable coins, are othe=
r
> users going to care enough to put in the effort to run new node software
> that resists the soft fork? Seems unlikely to me.
>
> How to Execute Burning
> In order to be as objective as possible, the goal would be to announce to
> the world that after a specific block height / timestamp, Bitcoin nodes
> will no longer accept transactions (or blocks containing such transaction=
s)
> that spend funds from any scripts other than the newly instituted quantum
> safe schemes.
>
> It could take a staggered approach to first freeze funds that are
> susceptible to long-range attacks such as those in P2PK scripts or those
> that exposed their public keys due to previously re-using addresses, but =
I
> expect the additional complexity would drive further controversy.
>
> How long should the grace period be in order to give the ecosystem time t=
o
> upgrade? I'd say a minimum of 1 year for software wallets to upgrade. We
> can only hope that hardware wallet manufacturers are able to implement po=
st
> quantum cryptography on their existing hardware with only a firmware upda=
te.
>
> Beyond that, it will take at least 6 months worth of block space for all
> users to migrate their funds, even in a best case scenario. Though if you
> exclude dust UTXOs you could probably get 95% of BTC value migrated in 1
> month. Of course this is a highly optimistic situation where everyone is
> completely focused on migrations - in reality it will take far longer.
>
> Regardless, I'd think that in order to reasonably uphold Bitcoin's
> conservatism it would be preferable to allow a 4 year migration window. I=
n
> the meantime, mining pools could coordinate emergency soft forking logic
> such that if quantum attackers materialized, they could accelerate the
> countdown to the quantum vulnerable funds burn.
>
> Random Tangential Benefits
> On the plus side, burning all quantum vulnerable bitcoin would allow us t=
o
> prune all of those UTXOs out of the UTXO set, which would also clean up a
> lot of dust. Dust UTXOs are a bit of an annoyance and there has even been=
 a
> recent proposal for how to incentivize cleaning them up.
>
> We should also expect that incentivizing migration of the entire UTXO set
> will create substantial demand for block space that will sustain a fee
> market for a fairly lengthy amount of time.
>
> In Summary
> While the moral quandary of violating any of Bitcoin's inviolable
> properties can make this a very complex issue to discuss, the game theory
> and incentives between burning vulnerable coins versus allowing them to b=
e
> claimed by entities with quantum supremacy appears to be a much simpler
> issue.
>
> I, for one, am not interested in rewarding quantum capable entities by
> inflating the circulating money supply just because some people lost thei=
r
> keys long ago and some laggards are not upgrading their bitcoin wallet's
> security.
>
> We can hope that this scenario never comes to pass, but hope is not a
> strategy.
>
> I welcome your feedback upon any of the above points, and contribution of
> any arguments I failed to consider.
>
> --
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<div dir=3D"ltr"><div dir=3D"ltr">I=E2=80=99m against letting quantum compu=
ters scoop up funds from addresses that don=E2=80=99t upgrade to quantum-re=
sistant.=C2=A0<br>Saulo=E2=80=99s idea of a free-market approach, leaving o=
ld coins up for grabs if people don=E2=80=99t move them, sounds fair at fir=
st. Let luck decide, right? But I worry it=E2=80=99d turn into a mess. If q=
uantum machines start cracking keys and snagging coins, it=E2=80=99s not ju=
st lost Satoshi-era stuff at risk. Plenty of active wallets, like those on =
the rich list Jameson mentioned, could get hit too. Imagine millions of BTC=
 flooding the market. Prices tank, trust in Bitcoin takes a dive, and we al=
l feel the pain. Freezing those vulnerable funds keeps that chaos in check.=
<br>Plus, =E2=80=9Cyour keys, your coins=E2=80=9D is Bitcoin=E2=80=99s hear=
t. If quantum tech can steal from you just because you didn=E2=80=99t upgra=
de fast enough, that promise feels shaky. Freezing funds after a heads-up p=
eriod (say, four years) protects that idea better than letting tech giants =
or rogue states play vampire with our network. It also nudges people to get=
 their act together and move to safer addresses, which strengthens Bitcoin =
long-term.<br>Saulo=E2=80=99s right that freezing coins could confuse folks=
 or spark a split like Ethereum Classic. But I=E2=80=99d argue quantum thef=
t would look worse. Bitcoin would seem broken, not just strict. A clear pla=
n and enough time to migrate could smooth things over. History=E2=80=99s on=
 our side too. Bitcoin=E2=80=99s fixed bugs before, like SegWit. This feels=
 like that, not a bailout.<br>So yeah, I=E2=80=99d rather see vulnerable co=
ins locked than handed to whoever builds the first quantum rig. It=E2=80=99=
s less about coddling people and more about keeping Bitcoin solid for every=
one. What do you all think?<br>Cheers,<br>Agust=C3=ADn<br><br></div><br><di=
v class=3D"gmail_quote gmail_quote_container"><div dir=3D"ltr" class=3D"gma=
il_attr">On Sun, Mar 23, 2025 at 10:29=E2=80=AFPM AstroTown &lt;<a href=3D"=
mailto:saulo@astrotown.de">saulo@astrotown.de</a>&gt; wrote:<br></div><bloc=
kquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:=
1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"auto"><div dir=3D"=
ltr"><span style=3D"color:rgb(0,0,0)">I believe that having some entity ann=
ounce the decision to freeze old UTXOs would be more damaging to Bitcoin=E2=
=80=99s image (and its value) than having them gathered by QC. This would c=
reate another version of Bitcoin, similar to Ethereum Classic, causing conf=
usion in the market.</span><div dir=3D"ltr"><div style=3D"color:rgb(0,0,0)"=
><br></div><div style=3D"color:rgb(0,0,0)">It would be better to simply imp=
lement the possibility of moving funds to a PQC address without a deadline,=
 allowing those who fail to do so to rely on luck to avoid having their coi=
ns stolen. Most coins would be migrated to PQC anyway, and in most cases, o=
nly the lost ones would remain vulnerable. This is the free-market way to s=
olve problems without imposing rules on everyone.</div><div style=3D"color:=
rgb(0,0,0)"><br></div><div style=3D"color:rgb(0,0,0)">Saulo Fonseca</div><d=
iv style=3D"color:rgb(0,0,0)"><br></div><div style=3D"color:rgb(0,0,0)"><br=
><blockquote type=3D"cite"><div>On 16. Mar 2025, at 15:15, Jameson Lopp &lt=
;<span dir=3D"ltr"><a href=3D"mailto:jameson.lopp@gmail.com" target=3D"_bla=
nk">jameson.lopp@gmail.com</a></span>&gt; wrote:</div><br><div><div dir=3D"=
ltr">The quantum computing debate is heating up. There are many controversi=
al aspects to this debate, including whether or not quantum computers will =
ever actually become a practical threat.<div><br>I won&#39;t tread into the=
 unanswerable question of how worried we should be about quantum computers.=
 I think it&#39;s far from a crisis, but given the difficulty in changing B=
itcoin it&#39;s worth starting to seriously discuss. Today I wish to focus =
on a philosophical quandary related to one of the decisions that would need=
 to be made if and when we implement a quantum safe signature scheme.<br><b=
r><font size=3D"6">Several Scenarios<br></font>Because this essay will refe=
rence game theory a fair amount, and there are many variables at play that =
could change the nature of the game, I think it&#39;s important to clarify =
the possible scenarios up front.<br><br>1. Quantum computing never material=
izes, never becomes a threat, and thus everything discussed in this essay i=
s moot.<br>2. A quantum computing threat materializes suddenly and Bitcoin =
does not have quantum safe signatures as part of the protocol. In this scen=
ario it would likely make the points below moot because Bitcoin would be fu=
ndamentally broken and it would take far too long to upgrade the protocol, =
wallet software, and migrate user funds in order to restore confidence in t=
he network.<br>3. Quantum computing advances slowly enough that we come to =
consensus about how to upgrade Bitcoin and post quantum security has been m=
inimally adopted by the time an attacker appears.<br>4. Quantum computing a=
dvances slowly enough that we come to consensus about how to upgrade Bitcoi=
n and post quantum security has been highly adopted by the time an attacker=
 appears.<br><br>For the purposes of this post, I&#39;m envisioning being i=
n situation 3 or 4.<br><br><font size=3D"6">To Freeze or not to Freeze?<br>=
</font>I&#39;ve started seeing more people weighing in on what is likely th=
e most contentious aspect of how a quantum resistance upgrade should be han=
dled in terms of migrating user funds. Should quantum vulnerable funds be l=
eft open to be swept by anyone with a sufficiently powerful quantum compute=
r OR should they be permanently locked?<br><br><blockquote class=3D"gmail_q=
uote" style=3D"margin:0px 0px 0px 0.8ex;border-left-color:rgb(204,204,204);=
padding-left:1ex">&quot;I don&#39;t see why old coins should be confiscated=
. The better option is to let those with quantum computers free up old coin=
s. While this might have an inflationary impact on bitcoin&#39;s price, to =
use a turn of phrase, the inflation is transitory. Those with low time pref=
erence should support returning lost coins to circulation.&quot;=C2=A0</blo=
ckquote><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex=
;border-left-color:rgb(204,204,204);padding-left:1ex">- Hunter Beast</block=
quote><div><br></div>On the other hand:</div><div><br><blockquote class=3D"=
gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left-color:rgb(204,20=
4,204);padding-left:1ex">&quot;Of course they have to be confiscated. If an=
d when (and that&#39;s a big if) the existence of a cryptography-breaking Q=
C becomes a credible threat, the Bitcoin ecosystem has no other option than=
 softforking out the ability to spend from signature schemes (including ECD=
SA and BIP340) that are vulnerable to QCs. The alternative is that millions=
 of BTC become vulnerable to theft; I cannot see how the currency can maint=
ain any value at all in such a setting. And this affects everyone; even tho=
se which diligently moved their coins to PQC-protected schemes.&quot;<br>- =
Pieter Wuille</blockquote><br>I don&#39;t think &quot;confiscation&quot; is=
 the most precise term to use, as the funds are not being seized and reassi=
gned. Rather, what we&#39;re really discussing would be better described as=
 &quot;burning&quot; - placing the funds=C2=A0<b>out of reach of everyone</=
b>.<br><br>Not freezing user funds is one of Bitcoin&#39;s inviolable prope=
rties. However, if quantum computing becomes a threat to Bitcoin&#39;s elli=
ptic curve cryptography,=C2=A0<b>an inviolable property of Bitcoin will be =
violated one way or another</b>.<br><br><font size=3D"6">Fundamental Proper=
ties at Risk<br></font>5 years ago I attempted to comprehensively categoriz=
e all of Bitcoin&#39;s fundamental properties that give it value.=C2=A0<a h=
ref=3D"https://nakamoto.com/what-are-the-key-properties-of-bitcoin/" target=
=3D"_blank">https://nakamoto.com/what-are-the-key-properties-of-bitcoin/<br=
></a><br>The particular properties in play with regard to this issue seem t=
o be:<br><br><b>Censorship Resistance</b>=C2=A0- No one should have the pow=
er to prevent others from using their bitcoin or interacting with the netwo=
rk.<br><br><b>Forward Compatibility</b>=C2=A0- changing the rules such that=
 certain valid transactions become invalid could undermine confidence in th=
e protocol.<br><br><b>Conservatism</b>=C2=A0- Users should not be expected =
to be highly responsive to system issues.<br><br>As a result of the above p=
rinciples, we have developed a strong meme (kudos to Andreas Antonopoulos) =
that goes as follows:<br><br><blockquote class=3D"gmail_quote" style=3D"mar=
gin:0px 0px 0px 0.8ex;border-left-color:rgb(204,204,204);padding-left:1ex">=
Not your keys, not your coins.</blockquote><br>I posit that the corollary t=
o this principle is:<br><br><blockquote class=3D"gmail_quote" style=3D"marg=
in:0px 0px 0px 0.8ex;border-left-color:rgb(204,204,204);padding-left:1ex">Y=
our keys, only your coins.</blockquote><br>A quantum capable entity breaks =
the corollary of this foundational principle. We secure our bitcoin with th=
e mathematical probabilities related to extremely large random numbers. You=
r funds are only secure because truly random large numbers should not be gu=
essable or discoverable by anyone else in the world.<br><br>This is the pri=
nciple behind the motto=C2=A0<i>vires in numeris</i>=C2=A0- strength in num=
bers. In a world with quantum enabled adversaries, this principle is null a=
nd void for many types of cryptography, including the elliptic curve digita=
l signatures used in Bitcoin.<br><br><font size=3D"6">Who is at Risk?<br></=
font>There has long been a narrative that Satoshi&#39;s coins and others fr=
om the Satoshi era of P2PK locking scripts that exposed the public key dire=
ctly on the blockchain will be those that get scooped up by a quantum &quot=
;miner.&quot; But unfortunately it&#39;s not that simple. If I had a powerf=
ul quantum computer, which coins would I target? I&#39;d go to the Bitcoin =
rich list and find the wallets that have exposed their public keys due to r=
e-using addresses that have previously been spent from. You can easily find=
 them at=C2=A0<a href=3D"https://bitinfocharts.com/top-100-richest-bitcoin-=
addresses.html" target=3D"_blank">https://bitinfocharts.com/top-100-richest=
-bitcoin-addresses.html</a><br><br>Note that a few of these wallets, like B=
itfinex / Kraken / Tether, would be slightly harder to crack because they a=
re multisig wallets. So a quantum attacker would need to reverse engineer 2=
 keys for Kraken or 3 for Bitfinex / Tether in order to spend funds. But ma=
ny are single signature.<br><br>Point being, it&#39;s not only the really o=
ld lost BTC that are at risk to a quantum enabled adversary, at least at ti=
me of writing. If we add a quantum safe signature scheme, we should expect =
those wallets to be some of the first to upgrade given their incentives.<br=
><br><font size=3D"6">The Ethical Dilemma: Quantifying Harm<br></font>Which=
 decision results in the most harm?<br><br>By making quantum vulnerable fun=
ds unspendable we potentially harm some Bitcoin users who were not paying a=
ttention and neglected to migrate their funds to a quantum safe locking scr=
ipt. This violates the &quot;conservativism&quot; principle stated earlier.=
 On the flip side, we prevent those funds plus far more lost funds from fal=
ling into the hands of the few privileged folks who gain early access to qu=
antum computers.<br><br>By leaving quantum vulnerable funds available to sp=
end, the same set of users who would otherwise have funds frozen are likely=
 to see them stolen. And many early adopters who lost their keys will event=
ually see their unreachable funds scooped up by a quantum enabled adversary=
.<br><br>Imagine, for example, being James Howells, who accidentally threw =
away a hard drive with 8,000 BTC on it, currently worth over $600M USD. He =
has spent a decade trying to retrieve it from the landfill where he knows i=
t&#39;s buried, but can&#39;t get permission to excavate. I suspect that, g=
iven the choice, he&#39;d prefer those funds be permanently frozen rather t=
han fall into someone else&#39;s possession - I know I would.<br><br>Allowi=
ng a quantum computer to access lost funds doesn&#39;t make those users any=
 worse off than they were before, however it=C2=A0<i>would</i>have a negati=
ve impact upon everyone who is currently holding bitcoin.<br><br>It&#39;s p=
rudent to expect significant economic disruption if large amounts of coins =
fall into new hands. Since a quantum computer is going to have a massive up=
 front cost, expect those behind it to desire to recoup their investment. W=
e also know from experience that when someone suddenly finds themselves in =
possession of 9+ figures worth of highly liquid assets, they tend to divers=
ify into other things by selling.<br><br>Allowing quantum recovery of bitco=
in is=C2=A0<i>tantamount to wealth redistribution</i>. What we&#39;d be all=
owing is for bitcoin to be redistributed from those who are ignorant of qua=
ntum computers to those who have won the technological race to acquire quan=
tum computers. It&#39;s hard to see a bright side to that scenario.<br><br>=
<font size=3D"6">Is Quantum Recovery Good for Anyone?</font><br><br>Does qu=
antum recovery HELP anyone? I&#39;ve yet to come across an argument that it=
&#39;s a net positive in any way. It certainly doesn&#39;t add any security=
 to the network. If anything, it greatly decreases the security of the netw=
ork by allowing funds to be claimed by those who did not earn them.<br><br>=
But wait, you may be thinking, wouldn&#39;t quantum &quot;miners&quot; have=
 earned their coins by all the work and resources invested in building a qu=
antum computer? I suppose, in the same sense that a burglar earns their spo=
ils by the resources they invest into surveilling targets and learning the =
skills needed to break into buildings. What I say &quot;earned&quot; I mean=
 through productive mutual trade.<br><br>For example:<br><br>* Investors ea=
rn BTC by trading for other currencies.<br>* Merchants earn BTC by trading =
for goods and services.<br>* Miners earn BTC by trading thermodynamic secur=
ity.<br>* Quantum miners don&#39;t trade anything, they are vampires feedin=
g upon the system.<br><br>There&#39;s no reason to believe that allowing qu=
antum adversaries to recover vulnerable bitcoin will be of benefit to anyon=
e other than the select few organizations that win the technological arms r=
ace to build the first such computers. Probably nation states and/or the to=
p few largest tech companies.<br><br>One could certainly hope that an organ=
ization with quantum supremacy is benevolent and acts in a &quot;white hat&=
quot; manner to return lost coins to their owners, but that&#39;s incredibl=
y optimistic and foolish to rely upon. Such a situation creates an insurmou=
ntable ethical dilemma of only recovering lost bitcoin rather than currentl=
y owned bitcoin. There&#39;s no way to precisely differentiate between the =
two; anyone can claim to have lost their bitcoin but if they have lost thei=
r keys then proving they ever had the keys becomes rather difficult. I imag=
ine that any such white hat recovery efforts would have to rely upon attest=
ations from trusted third parties like exchanges.<br><br>Even if the first =
actor with quantum supremacy is benevolent, we must assume the technology c=
ould fall into adversarial hands and thus think adversarially about the pot=
ential worst case outcomes. Imagine, for example, that North Korea continue=
s scooping up billions of dollars from hacking crypto exchanges and decides=
 to invest some of those proceeds into building a quantum computer for the =
biggest payday ever...<br><br><font size=3D"6">Downsides to Allowing Quantu=
m Recovery</font><br>Let&#39;s think through an exhaustive list of pros and=
 cons for allowing or preventing the seizure of funds by a quantum adversar=
y.<br><br><font size=3D"4">Historical Precedent</font><br>Previous protocol=
 vulnerabilities weren=E2=80=99t celebrated as &quot;fair game&quot; but ra=
ther were treated as failures to be remediated. Treating quantum theft diff=
erently risks rewriting Bitcoin=E2=80=99s history as a free-for-all rather =
than a system that seeks to protect its users.<br><br><font size=3D"4">Viol=
ation of Property Rights</font><br>Allowing a quantum adversary to take con=
trol of funds undermines the fundamental principle of cryptocurrency - if y=
ou keep your keys in your possession, only you should be able to access you=
r money. Bitcoin is built on the idea that private keys secure an individua=
l=E2=80=99s assets, and unauthorized access (even via advanced tech) is the=
ft, not a legitimate transfer.<br><br><font size=3D"4">Erosion of Trust in =
Bitcoin</font><br>If quantum attackers can exploit vulnerable addresses, co=
nfidence in Bitcoin as a secure store of value would collapse. Users and in=
vestors rely on cryptographic integrity, and widespread theft could drive a=
doption away from Bitcoin, destabilizing its ecosystem.<br><br>This is esse=
ntially the counterpoint to claiming the burning of vulnerable funds is a v=
iolation of property rights. While some will certainly see it as such, othe=
rs will find the apathy toward stopping quantum theft to be similarly conce=
rning.<br><br><font size=3D"4">Unfair Advantage</font><br>Quantum attackers=
, likely equipped with rare and expensive technology, would have an unjust =
edge over regular users who lack access to such tools. This creates an ineq=
uitable system where only the technologically elite can exploit others, con=
tradicting Bitcoin=E2=80=99s ethos of decentralized power.<br><br>Bitcoin i=
s designed to create an asymmetric advantage for DEFENDING one&#39;s wealth=
. It&#39;s supposed to be impractically expensive for attackers to crack th=
e entropy and cryptography protecting one&#39;s coins. But now we find ours=
elves discussing a situation where this asymmetric advantage is compromised=
 in favor of a specific class of attackers.<br><br><font size=3D"4">Economi=
c Disruption</font><br>Large-scale theft from vulnerable addresses could cr=
ash Bitcoin=E2=80=99s price as quantum recovered funds are dumped on exchan=
ges. This would harm all holders, not just those directly targeted, leading=
 to broader financial chaos in the markets.<br><br><font size=3D"4">Moral R=
esponsibility</font><br>Permitting theft via quantum computing sets a prece=
dent that technological superiority justifies unethical behavior. This is e=
ssentially taking a &quot;code is law&quot; stance in which we refuse to ad=
mit that both code and laws can be modified to adapt to previously unforese=
en situations.<br><br>Burning of coins can certainly be considered a form o=
f theft, thus I think it&#39;s worth differentiating the two different thef=
ts being discussed:<br><br>1. self-enriching &amp; likely malicious<br>2. h=
arm prevention &amp; not necessarily malicious<br><br>Both options lack the=
 consent of the party whose coins are being burnt or transferred, thus I th=
ink the simple argument that theft is immoral becomes a wash and it&#39;s i=
mportant to drill down into the details of each.<br><br><font size=3D"4">In=
centives Drive Security</font><br>I can tell you from a decade of working i=
n Bitcoin security - the average user is lazy and is a procrastinator. If B=
itcoiners are given a &quot;drop dead date&quot; after which they know vuln=
erable funds will be burned, this pressure accelerates the adoption of post=
-quantum cryptography and strengthens Bitcoin long-term. Allowing vulnerabl=
e users to delay upgrading indefinitely will result in more laggards, leavi=
ng the network more exposed when quantum tech becomes available.<br><br><fo=
nt size=3D"6">Steel Manning<br></font>Clearly this is a complex and controv=
ersial topic, thus it&#39;s worth thinking through the opposing arguments.<=
br><br><font size=3D"4">Protecting Property Rights</font><br>Allowing quant=
um computers to take vulnerable bitcoin could potentially be spun as a hard=
 money narrative - we care so greatly about not violating someone&#39;s acc=
ess to their coins that we allow them to be stolen!<br><br>But I think the =
flip side to the property rights narrative is that burning vulnerable coins=
 prevents said property from falling into undeserving hands. If the entire =
Bitcoin ecosystem just stands around and allows quantum adversaries to clai=
m funds that rightfully belong to other users, is that really a &quot;win&q=
uot; in the &quot;protecting property rights&quot; category? It feels more =
like apathy to me.<br><br>As such, I think the &quot;protecting property ri=
ghts&quot; argument is a wash.<br><br><font size=3D"4">Quantum Computers Wo=
n&#39;t Attack Bitcoin</font><br>There is a great deal of skepticism that s=
ufficiently powerful quantum computers will ever exist, so we shouldn&#39;t=
 bother preparing for a non-existent threat. Others have argued that even i=
f such a computer was built, a quantum attacker would not go after bitcoin =
because they wouldn&#39;t want to reveal their hand by doing so, and would =
instead attack other infrastructure.<br><br>It&#39;s quite difficult to qua=
ntify exactly how valuable attacking other infrastructure would be. It also=
 really depends upon when an entity gains quantum supremacy and thus if by =
that time most of the world&#39;s systems have already been upgraded. While=
 I think you could argue that certain entities gaining quantum capability m=
ight not attack Bitcoin, it would only delay the inevitable - eventually so=
mebody will achieve the capability who decides to use it for such an attack=
.<br><br><font size=3D"4">Quantum Attackers Would Only Steal Small Amounts<=
/font><br>Some have argued that even if a quantum attacker targeted bitcoin=
, they&#39;d only go after old, likely lost P2PK outputs so as to not arous=
e suspicion and cause a market panic.<br><br>I&#39;m not so sure about that=
; why go after 50 BTC at a time when you could take 250,000 BTC with the sa=
me effort as 50 BTC? This is a classic &quot;zero day exploit&quot; game th=
eory in which an attacker knows they have a limited amount of time before s=
omeone else discovers the exploit and either benefits from it or patches it=
. Take, for example, the recent ByBit attack - the highest value crypto hac=
k of all time. Lazarus Group had compromised the Safe wallet front end Java=
Script app and they could have simply had it reassign ownership of everyone=
&#39;s Safe wallets as they were interacting with their wallet. But instead=
 they chose to only specifically target ByBit&#39;s wallet with $1.5 billio=
n in it because they wanted to maximize their extractable value. If Lazarus=
 had started stealing from every wallet, they would have been discovered qu=
ickly and the Safe web app would likely have been patched well before any b=
illion dollar wallets executed the malicious code.<br><br>I think the &quot=
;only stealing small amounts&quot; argument is strongest for Situation #2 d=
escribed earlier, where a quantum attacker arrives before quantum safe cryp=
tography has been deployed across the Bitcoin ecosystem. Because if it beca=
me clear that Bitcoin&#39;s cryptography was broken AND there was nowhere s=
afe for vulnerable users to migrate, the only logical option would be for e=
veryone to liquidate their bitcoin as quickly as possible. As such, I don&#=
39;t think it applies as strongly for situations in which we have a migrati=
on path available.<br><br><font size=3D"4">The 21 Million Coin Supply Shoul=
d be in Circulation</font><br>Some folks are arguing that it&#39;s importan=
t for the &quot;circulating / spendable&quot; supply to be as close to 21M =
as possible and that having a significant portion of the supply out of circ=
ulation is somehow undesirable.<br><br>While the &quot;21M BTC&quot; attrib=
ute is a strong memetic narrative, I don&#39;t think anyone has ever expect=
ed that it would all be in circulation. It has always been understood that =
many coins will be lost, and that&#39;s actually part of the game theory of=
 owning bitcoin!<br><br>And remember, the 21M number in and of itself is no=
t a particularly important detail - it&#39;s not even mentioned in the whit=
epaper. What&#39;s important is that the supply is well known and not subje=
ct to change.<br><br><font size=3D"4">Self-Sovereignty and Personal Respons=
ibility</font><br>Bitcoin=E2=80=99s design empowers individuals to control =
their own wealth, free from centralized intervention. This freedom comes wi=
th the burden of securing one&#39;s private keys. If quantum computing can =
break obsolete cryptography, the fault lies with users who didn&#39;t move =
their funds to quantum safe locking scripts. Expecting the network to shiel=
d users from their own negligence undermines the principle that you, and no=
t a third party, are accountable for your assets.<br><br>I think this is ge=
nerally a fair point that &quot;the community&quot; doesn&#39;t owe you any=
thing in terms of helping you. I think that we do, however, need to conside=
r the incentives and game theory in play with regard to quantum safe Bitcoi=
ners vs quantum vulnerable Bitcoiners. More on that later.<br><br><font siz=
e=3D"4">Code is Law</font><br>Bitcoin operates on transparent, immutable ru=
les embedded in its protocol. If a quantum attacker uses superior technolog=
y to derive private keys from public keys, they=E2=80=99re not &quot;hackin=
g&quot; the system - they&#39;re simply following what&#39;s mathematically=
 permissible within the current code. Altering the protocol to stop this in=
troduces subjective human intervention, which clashes with the objective, d=
eterministic nature of blockchain.<br><br>While I tend to agree that code i=
s law, one of the entire points of laws is that they can be amended to impr=
ove their efficacy in reducing harm. Leaning on this point seems more like =
a pro-ossification stance that it&#39;s better to do nothing and allow harm=
 to occur rather than take action to stop an attack that was foreseen far i=
n advance.<br><br><font size=3D"4">Technological Evolution as a Feature, No=
t a Bug</font><br>It&#39;s well known that cryptography tends to weaken ove=
r time and eventually break. Quantum computing is just the next step in thi=
s progression. Users who fail to adapt (e.g., by adopting quantum-resistant=
 wallets when available) are akin to those who ignored technological advanc=
ements like multisig or hardware wallets. Allowing quantum theft incentiviz=
es innovation and keeps Bitcoin=E2=80=99s ecosystem dynamic, punishing comp=
lacency while rewarding vigilance.<br><br><font size=3D"4">Market Signals D=
rive Security</font><br>If quantum attackers start stealing funds, it sends=
 a clear signal to the market: upgrade your security or lose everything. Th=
is pressure accelerates the adoption of post-quantum cryptography and stren=
gthens Bitcoin long-term. Coddling vulnerable users delays this necessary e=
volution, potentially leaving the network more exposed when quantum tech be=
comes widely accessible. Theft is a brutal but effective teacher.<br><br><f=
ont size=3D"4">Centralized Blacklisting Power</font><br>Burning vulnerable =
funds requires centralized decision-making - a soft fork to invalidate cert=
ain transactions. This sets a dangerous precedent for future interventions,=
 eroding Bitcoin=E2=80=99s decentralization. If quantum theft is blocked, w=
hat=E2=80=99s next - reversing exchange hacks? The system must remain neutr=
al, even if it means some lose out.<br><br>I think this could be a potentia=
l slippery slope if the proposal was to only burn specific addresses. Rathe=
r, I&#39;d expect a neutral proposal to burn all funds in locking script ty=
pes that are known to be quantum vulnerable. Thus, we could eliminate any s=
ubjectivity from the code.<br><br><font size=3D"4">Fairness in Competition<=
/font><br>Quantum attackers aren&#39;t cheating; they&#39;re using publicly=
 available physics and math. Anyone with the resources and foresight can bu=
ild or access quantum tech, just as anyone could mine Bitcoin in 2009 with =
a CPU. Early adopters took risks and reaped rewards; quantum innovators are=
 doing the same. Calling it =E2=80=9Cunfair=E2=80=9D ignores that Bitcoin h=
as never promised equality of outcome - only equality of opportunity within=
 its rules.<br><br>I find this argument to be a mischaracterization because=
 we&#39;re not talking about CPUs. This is more akin to talking about ASICs=
, except each ASIC costs millions if not billions of dollars. This is out o=
f reach from all but the wealthiest organizations.<br><br><font size=3D"4">=
Economic Resilience</font><br>Bitcoin has weathered thefts before (MTGOX, B=
itfinex, FTX, etc) and emerged stronger. The market can absorb quantum loss=
es, with unaffected users continuing to hold and new entrants buying in at =
lower prices. Fear of economic collapse overestimates the impact - the netw=
ork=E2=80=99s antifragility thrives on such challenges.<br><br>This is a bi=
g grey area because we don&#39;t know when a quantum computer will come onl=
ine and we don&#39;t know how quickly said computers would be able to steal=
 bitcoin. If, for example, the first generation of sufficiently powerful qu=
antum computers were stealing less volume than the current block reward the=
n of course it will have minimal economic impact. But if they&#39;re taking=
 thousands of BTC per day and bringing them back into circulation, there wi=
ll likely be a noticeable market impact as it absorbs the new supply.<br><b=
r>This is where the circumstances will really matter. If a quantum attacker=
 appears AFTER the Bitcoin protocol has been upgraded to support quantum re=
sistant cryptography then we should expect the most valuable active wallets=
 will have upgraded and the juiciest target would be the 31,000 BTC in the =
address 12ib7dApVFvg82TXKycWBNpN8kFyiAN1dr which has been dormant since 201=
0. In general I&#39;d expect that the amount of BTC re-entering the circula=
ting supply would look somewhat similar to the mining emission curve: volum=
e would start off very high as the most valuable addresses are drained and =
then it would fall off as quantum computers went down the list targeting ad=
dresses with less and less BTC.<br><br>Why is economic impact a factor wort=
h considering? Miners and businesses in general. More coins being liquidate=
d will push down the price, which will negatively impact miner revenue. Sim=
ilarly, I can attest from working in the industry for a decade, that lower =
prices result in less demand from businesses across the entire industry. As=
 such, burning quantum vulnerable bitcoin is good for the entire industry.<=
br><br><font size=3D"4">Practicality &amp; Neutrality of Non-Intervention</=
font><br>There=E2=80=99s no reliable way to distinguish =E2=80=9Ctheft=E2=
=80=9D from legitimate &quot;white hat&quot; key recovery. If someone loses=
 their private key and a quantum computer recovers it, is that stealing or =
reclaiming? Policing quantum actions requires invasive assumptions about in=
tent, which Bitcoin=E2=80=99s trustless design can=E2=80=99t accommodate. L=
etting the chips fall where they may avoids this mess.<br><br><font size=3D=
"4">Philosophical Purity</font><br>Bitcoin rejects bailouts. It=E2=80=99s a=
 cold, hard system where outcomes reflect preparation and skill, not sentim=
entality. If quantum computing upends the game, that=E2=80=99s the point - =
Bitcoin isn=E2=80=99t meant to be safe or fair in a nanny-state sense; it=
=E2=80=99s meant to be free. Users who lose funds to quantum attacks are ca=
sualties of liberty and their own ignorance, not victims of injustice.<br><=
br><font size=3D"6">Bitcoin&#39;s DAO Moment</font><br>This situation has s=
ome similarities to The DAO hack of an Ethereum smart contract in 2016, whi=
ch resulted in a fork to stop the attacker and return funds to their origin=
al owners. The game theory is similar because it&#39;s a situation where a =
threat is known but there&#39;s some period of time before the attacker can=
 actually execute the theft. As such, there&#39;s time to mitigate the atta=
ck by changing the protocol.<br><br>It also created a schism in the communi=
ty around the true meaning of &quot;code is law,&quot; resulting in Ethereu=
m Classic, which decided to allow the attacker to retain control of the sto=
len funds.<br><br>A soft fork to burn vulnerable bitcoin could certainly re=
sult in a hard fork if there are enough miners who reject the soft fork and=
 continue including transactions.<br><br><font size=3D"6">Incentives Matter=
</font><br>We can wax philosophical until the cows come home, but what are =
the actual incentives for existing Bitcoin holders regarding this decision?=
<br><br><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex=
;border-left-color:rgb(204,204,204);padding-left:1ex">&quot;Lost coins only=
 make everyone else&#39;s coins worth slightly more. Think of it as a donat=
ion to everyone.&quot; - Satoshi Nakamoto</blockquote><br>If true, the coro=
llary is:<br><br><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px =
0px 0.8ex;border-left-color:rgb(204,204,204);padding-left:1ex">&quot;Quantu=
m recovered coins only make everyone else&#39;s coins worth less. Think of =
it as a theft from everyone.&quot; - Jameson Lopp</blockquote><br>Thus, ass=
uming we get to a point where quantum resistant signatures are supported wi=
thin the Bitcoin protocol, what&#39;s the incentive to let vulnerable coins=
 remain spendable?<br><br>* It&#39;s not good for the actual owners of thos=
e coins. It disincentivizes owners from upgrading until perhaps it&#39;s to=
o late.<br>* It&#39;s not good for the more attentive / responsible owners =
of coins who have quantum secured their stash. Allowing the circulating sup=
ply to balloon will assuredly reduce the purchasing power of all bitcoin ho=
lders.<br><br><font size=3D"6">Forking Game Theory</font><br>From a game th=
eory point of view, I see this as incentivizing users to upgrade their wall=
ets. If you disagree with the burning of vulnerable coins, all you have to =
do is move your funds to a quantum safe signature scheme. Point being, I do=
n&#39;t see there being an economic majority (or even more than a tiny mino=
rity) of users who would fight such a soft fork. Why expend significant res=
ources fighting a fork when you can just move your coins to a new address?<=
br><br>Remember that blocking spending of certain classes of locking script=
s is a tightening of the rules - a soft fork. As such, it can be meaningful=
ly enacted and enforced by a mere majority of hashpower. If miners generall=
y agree that it&#39;s in their best interest to burn vulnerable coins, are =
other users going to care enough to put in the effort to run new node softw=
are that resists the soft fork? Seems unlikely to me.<br><br><font size=3D"=
6">How to Execute Burning</font><br>In order to be as objective as possible=
, the goal would be to announce to the world that after a specific block he=
ight / timestamp, Bitcoin nodes will no longer accept transactions (or bloc=
ks containing such transactions) that spend funds from any scripts other th=
an the newly instituted quantum safe schemes.<br><br>It could take a stagge=
red approach to first freeze funds that are susceptible to long-range attac=
ks such as those in P2PK scripts or those that exposed their public keys du=
e to previously re-using addresses, but I expect the additional complexity =
would drive further controversy.<br><br>How long should the grace period be=
 in order to give the ecosystem time to upgrade? I&#39;d say a minimum of 1=
 year for software wallets to upgrade. We can only hope that hardware walle=
t manufacturers are able to implement post quantum cryptography on their ex=
isting hardware with only a firmware update.<br><br>Beyond that, it will ta=
ke at least 6 months worth of block space for all users to migrate their fu=
nds, even in a best case scenario. Though if you exclude dust UTXOs you cou=
ld probably get 95% of BTC value migrated in 1 month. Of course this is a h=
ighly optimistic situation where everyone is completely focused on migratio=
ns - in reality it will take far longer.<br><br>Regardless, I&#39;d think t=
hat in order to reasonably uphold Bitcoin&#39;s conservatism it would be pr=
eferable to allow a 4 year migration window. In the meantime, mining pools =
could coordinate emergency soft forking logic such that if quantum attacker=
s materialized, they could accelerate the countdown to the quantum vulnerab=
le funds burn.<br><br><font size=3D"6">Random Tangential Benefits</font><br=
>On the plus side, burning all quantum vulnerable bitcoin would allow us to=
 prune all of those UTXOs out of the UTXO set, which would also clean up a =
lot of dust. Dust UTXOs are a bit of an annoyance and there has even been a=
 recent proposal for how to incentivize cleaning them up.<br><br>We should =
also expect that incentivizing migration of the entire UTXO set will create=
 substantial demand for block space that will sustain a fee market for a fa=
irly lengthy amount of time.<br><br><font size=3D"6">In Summary</font><br>W=
hile the moral quandary of violating any of Bitcoin&#39;s inviolable proper=
ties can make this a very complex issue to discuss, the game theory and inc=
entives between burning vulnerable coins versus allowing them to be claimed=
 by entities with quantum supremacy appears to be a much simpler issue.<br>=
<br>I, for one, am not interested in rewarding quantum capable entities by =
inflating the circulating money supply just because some people lost their =
keys long ago and some laggards are not upgrading their bitcoin wallet&#39;=
s security.<br><br>We can hope that this scenario never comes to pass, but =
hope is not a strategy.<br><br>I welcome your feedback upon any of the abov=
e points, and contribution of any arguments I failed to consider.</div></di=
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