[ExI] [Extropolis] DIY Quantum Protection for Bitcoin

[John Clark]

On Mon, Jun 1, 2026 at 10:21 PM Jason Resch via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

*> The most scalable quantum computing technology is the "neutral atom"
> quantum computer, *


*So say the neutral atom people, but plenty would dispute their claim. *

*> which is estimated to take at least a week to break an elliptic curve
> key, so following proper key hygiene one should be protected even after
> cryptographically relevant quantum computers emerge*


*The amount of time a quantum computer would need to solve a problem
depends on the speed of its individual components, the number of errors
those components produce (because the fewer errors the less time you need
to correct those errors), and the number of Qubits the computer
has. Neutral Atom is just one of the technologies being pursued, they all
have advantages and disadvantages.*

*As of today there is no clear front runner but Superconducting Josephson
Junctions is probably slightly ahead, it certainly has the most money
behind it being backed by IBM, Google and others. Its individual components
are the second fastest of the lot and the chips can be manufactured using
existing conventional semiconductor techniques. Scaling up is difficult,
however recently there has been significant progress. *

*Neutral Atom is the second easiest to scale up to a large number of
Qubits, but it also produces more errors then other technologies, and the
errors produced are the most difficult to correct. Its individual
components are also very slow. *

*Trapped Ions produce the second fewest errors and the errors that are
produced are easy to correct, but the gates are extremely slow and it's not
clear how to scale up to a useful size.*

*Silicon Spin Qubits is being pursued by Intel, it would give you the
second smallest Qbits and second densest array of them, and it would be
compatible with existing chip manufacturing technology, but the electronics
needed to control it are quite difficult and very complex.*

*Photonic Quantum Computing can operate at room temperature and long-range
communication is easy, but single-photon generation is required and such
generators are difficult to make, and its two-Qubit gates produce a lot of
errors. *

*Topological Quantum Computing is BY FAR the most ambitious approach and
it's the technology that Microsoft is pursuing, if they are successful it
will blow all the other methods completely out of the water in every
consideration you care to name, except compatibility with existing
semiconductor manufacturing techniques. But unlike all the other methods,
which are just engineering challenges, most physicists are only about 85%
certain that such a machine is scientifically possible. *

*The point I'm trying to make is that if your bitcoin security is based on
a hope that you will be able to outrun a large fault tolerant quantum
computer then I fear you are headed towards an economic catastrophe. *

*John K Clark*







>
> On Mon, Jun 1, 2026, 3:39 PM John Clark via extropy-chat <
> extropy-chat at lists.extropy.org> wrote:
>
>> On Mon, Jun 1, 2026 at 2:34 PM Stuart LaForge <avant at sollegro.com> wrote:
>>
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>>> *> Ok, so I think I have come up with a simple low technology method of
>>> safeguarding bitcoin against Quantum computing algorithms like Shor's.First
>>> you need to but 2 hardware cold wallets (e.g. Trezor, Ledger, etc.) Create
>>> a seed phrase to generate a public key with one of them and send your BTC
>>> to it.When you want to spend or transfer bitcoin, you set up (or reset) a
>>> seed phrase on your second wallet. Spend whatever bitcoin you need to and
>>> then transfer the remaining balance to the second wallet. When you
>>> spend/send bitcoin, the public key of the sending wallet gets exposed on
>>> the blockchain in a way that a quantum computer could use it to crack the
>>> private key for the spending wallet, so the idea is to empty that wallet
>>> completely. The public key of the receiving wallet is kept secret because
>>> it does not show up anywhere during the transaction. The only private key
>>> that a quantum computer could derive would be for the empty wallet that you
>>> no longer use.Then when you want to spend/send money from your second
>>> wallet, factory reset the original wallet and create a new seed phrase for
>>> it to generate a novel public. Spend your bitcoin from the second wallet
>>> and immediately send the remaining balance to the, now reset 1st wallet
>>> that has a brand new seed phrase / public key that has never been exposed
>>> on the blockchain and cannot be used to hack your private key.*
>>>
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>>> *Then, when you want to perform another transaction, rinse and repeat.
>>> Always resetting and reseeding the unused wallet to get a fresh public key
>>> before use. With two hardware wallets, you should be able to keep this up
>>> indefinitely. It is a little bit of a hassle, but from what I understand of
>>> the bitcoin protocol, it should keep your bitcoins safe from quantum
>>> computing algorithms with existing technology. Let me know if you find a
>>> weakness in this scheme.*
>>
>>
>> *Keeping the public key unexposed is a well known defense and it does
>> offer a little protection but the trouble is the public key isn't just
>> exposed when you initiate a transaction, it's exposed from the moment the
>> transaction hits the holding area where unconfirmed transactions wait in a
>> decentralized queue before being processed by miners, depending on how busy
>> the network is that could be anywhere from a few minutes to a few hours*,
>> and* in the quantum world *that is a* long time*;* a sufficiently
>> powerful quantum computer could crack your private key faster than block
>> confirmation time. Also, if anybody has ever sent to an address more than
>> once then those coins are already exposed to a future quantum attacker*. *And
>> when it comes to early bitcoins, like Satoshi's one million bitcoins, the
>> public key is directly in the output script and so the coins are already
>> fully exposed.*
>>
>
>
> The most scalable quantum computing technology is the "neutral atom"
> quantum computer, which is estimated to take at least a week to break an
> elliptic curve key, so following proper key hygiene one should be protected
> even after cryptographically relevant quantum computers emerge.
>
> Jason
>
>
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