[ExI] [Extropolis] DIY Quantum Protection for Bitcoin

[Jason Resch]

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.*
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> *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.*
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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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