20th February 2026 > > The quantum threat & your part in its downfall.

tl;dr

A non-technical introduction to the potential threat posed by currently non-existent quantum computers, and a simple means of guaranteeing that your BTC stash remains forever quantum resistant.

Market Snap

Market Wrap

Google searches for “BTC going to zero” are at the highest level since the collapse of FTX. The contrarian in me knows for sure this is a very positive sign.

Curious Cryptos’ Commentary – The quantum threat & your part in its downfall

Consensus appears to be that a quantum computer that is both powerful enough and stable enough to break elliptic curve signatures at the heart of ECDSA cryptography is anywhere from ten to twenty years away. The most aggressive timetable is just a few years away. I cannot give an honest critique of these predictions except to say that the advances we are seeing in A.I. could plausibly shorten the timescale compared to a world without A.I.

Developing a powerful and stable quantum computer can likely only be achieved in a partnership with government. I am firmly of the opinion that once we reach that milestone the concerns about what hostile countries – China in particular – will do with it to disrupt our lives far outweigh any concerns about cryptos. However, our focus here is a narrow one, so issues with our clean energy power systems being switched off, electric cars racing around the streets with no concern for human safety, the spilling of personal, corporate, and government secrets, the destruction of the NHS’ archaic databases, and all the myriad other objectives that Xi and his henchmen have laid out in their “World Domination Plan for the Subjugation and Enslavement of all Capitalists 2033 - 2038” – to which the CCC has privileged access – must take a back seat for now.

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The first question to consider is whether the advent of a powerful and stable quantum computer destroys the usability of cryptos, and the very clear answer is, not at all. There are already several experimental quantum resistant cryptos in circulation. Plans are being advanced to ensure that ETH will be ready within a reasonable timescale. BTC perhaps less so in some respects. The stablecoin revolution, the tokenisation revolution, and the inexorable rise of autonomous A.I. agents will continue apace untroubled by the quantum threat.

Which is all very nice, but what of our BTC bags?

In the next part of this missive, I will share with you a simple and effective way of ensuring that your personal BTC stash is quantum resistant regardless of any protocol level mitigation strategies. I will explain with as little technical knowledge as possible the theory and the practical steps needed to make your BTC safe from a quantum computer attack. But first, let us consider the situation that all active coins have been made quantum resistant by following my advice, but that inactive, old coins, that have not moved for years or decades (the Satoshi stash is a case in point) will fall foul of a quantum attack.

It is estimated that 3-5mm BTC are considered lost including the Satoshi stash, a whopping 15-25% of all coins that will ever be in existence. A quantum attacker may be able to access those coins, if no quantum resistant protocol was implemented, effectively increasing the supply of BTC by a fifth or so. At today’s price of $67k, an influx of supply of that size would theoretically lead to a price a little higher than $50k, a drop that is within the normal boundaries of a bear market, if indeed that is what we are experiencing right now.

Back in the real world, as opposed to the theoretical world, markets always massively overreact especially to threats which the popular press and those who lack natural curiosity declare to be existential. The short-term impact of a working quantum computer would result in an unjustified sell-off to a degree that would provide simply the best entry price that will ever be available again to long-term investors. Bring it on, I say.

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Having put our minds at rest on that point, we must now make sure that our personal stash is safe from a quantum attack. To fully understand how to do this so that we do it right, we must now turn our attention to understanding a little more about how cryptography has been implemented to create BTC.

Your twenty-four-word seed phrase is the basis for all your private keys, and your public keys. Your randomly generated seed phrase can never be accidentally replicated – there are approximately 10^77 possible combinations, an unfeasibly large number for us mere mortals to comprehend, but by way of comparison, estimates suggest 10^80 atoms in the observable universe. I told you it was a large number.

The quantum computer threat is a very specific one – it will be able to derive the private key from a public key, a feat that is currently impossible to achieve. The private key is used to sign transactions effectively proving ownership of the contents of the wallet identified by the public key. A quantum attacker armed with just the public key can spend the cryptos associated with that public key.

Old style wallets using P2PK (Pay-to-Public-Key) published the public key of both the sending wallet and the receiving wallet on the blockchain. These coins are at the highest risk from an attack by a functioning quantum computer. Later wallets using P2PKH (Pay-to-Public-Key-Hash) are not immediately at risk as the public key of the receiving wallet is not identified on the blockchain. Instead, a cryptographic hash of the receiving wallet’s public key is shown. No quantum computer can derive the actual public key from that hash.

However, if you spend BTC from an address, the blockchain will record in full detail the public key as the sending wallet. Any unspent coins in the form of a UTXO (unspent transaction output) in that address are then at risk from a quantum attack.

So, to make your personal stash quantum resistant, you have a single objective to achieve – any time you spend BTC from your wallet, any remaining coins must be moved to a new address created from a new private key.

A simple enough objective in principle, but how do you do that in practice?

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If you have not yet furnished yourself with a Ledger Nano, stroll into the bathroom, take a long, very long look at yourself, and realise you are not taking crypto custody seriously enough. Do something about it.

Assuming you do have a Ledger Nano, and you are using the standard process embedded within Ledger, the functionality of moving unspent BTC into a new public address derived from a new private key controlled by your seed phrase happens automatically. Lovely, no issues at all.

Except for maybe one concern, outside of the scope of quantum attacks, but related to privacy instead.

Every time you receive BTC you should use a new public address. Again, Ledger will automatically generate a new address for you each time, but of course you always have the option to re-use an old one. If you do that, your on-chain activity becomes much easier to piece together by a third-party, maliciously or otherwise. That is something I always try to avoid facilitating. Incidentally, using a new address each time negates any risk from the address poisoning scammers who continually bombard our wallets with tiny amounts of cryptos.

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In conclusion, the quantum threat is a real one, but it is not existential as portrayed by some of the alarmist naysaying journalists, and at worst, over the medium term, will simply mean an effective increase in the circulating supply of BTC, reducing the value of each BTC by maybe a fifth compared to a world without quantum computers. That is a far from disastrous outcome in general.

Your task is to ensure your personal BTC is quantum safe. Use Ledger, move coins out of any addresses that have previously spent BTC into a new Ledger generated address, and always use new addresses to receive coins. If you have manually reused old wallets or addresses, may I suggest an immediate migration to a new Ledger generated account, long before we get close to the reality of a functioning quantum computer.

Bingo, you are personally quantum resistant, and you have maximised your privacy, a very pleasing outcome for all concerned. If you need some personal guidance or help the CCC research team stands ready to ensure you are quantum resistant.