This misunderstanding is not trivial. As quantum technology accelerates, so too must our understanding of what truly protects Bitcoin, and where its future risks lie.
What Bitcoin Actually Uses: Not Encryption, But Cryptography
Bitcoin doesn’t use encryption to hide data. There’s no ciphertext being decoded with a secret key. Instead, Bitcoin leverages digital signatures and cryptographic hash functions, tools that are foundational to trustless systems but serve very different roles than traditional encryption.
Here’s how it breaks down:
- ECDSA (Elliptic Curve Digital Signature Algorithm) is used to prove ownership of Bitcoin. When you spend BTC, you’re signing the transaction with your private key.
- SHA-256, a cryptographic hash function, is used in mining (proof-of-work), address generation, and transaction identification.
Neither of these is “encryption” in the conventional sense (like AES or RSA), so Back is technically right. But that doesn’t mean quantum computers pose no risk.
The Real Threat: Shor’s Algorithm and Bitcoin’s Digital Signatures
Quantum computers, once mature, are expected to be able to run Shor’s algorithm, which can efficiently break widely used public-key cryptographic systems, including ECDSA.
This is where Bitcoin’s vulnerability lies.
Every Bitcoin transaction reveals the public key of the sender. With a powerful enough quantum computer, an attacker could compute the corresponding private key, allowing them to steal the associated funds. This turns every previously spent output into a potential attack vector.
In practice, this means:
- Unspent funds with only a Bitcoin address (a hash of the public key) are relatively safe.
- Funds in active use, where the public key is exposed, are vulnerable in a post-quantum world.
This is not theoretical hand-waving. Researchers estimate that a sufficiently powerful quantum computer, with several million qubits and low enough error rates, could compromise ECDSA. We’re not there yet, but we’re also not far enough away to ignore it.
What About Hash Functions Like SHA-256?
Bitcoin also relies on SHA-256, especially for mining. Quantum computers would use Grover’s algorithm to target hash functions, but this only offers a quadratic speedup, meaning SHA-256 would go from 2²⁵⁶ to 2¹²⁸ security. That’s still strong by today’s standards, though it might warrant a shift to longer hash sizes in the distant future.
So while quantum computing presents a theoretical threat to Bitcoin mining and address privacy, digital signatures remain the most immediate concern.
Timing the Quantum Threat
The good news? No quantum computer currently exists that can crack ECDSA. The bad news? Once such a machine is built, it could retroactively target exposed public keys. That means:
- Every previously broadcast transaction could become a liability.
- Attackers could sweep old wallets unless users migrate their funds to quantum-resistant addresses.
This isn’t paranoia: it’s a plausible future.
Are We Ready for Post-Quantum Bitcoin?
In theory, yes. Bitcoin can be upgraded via soft or hard forks to use quantum-resistant digital signature schemes. Algorithms like Lattice-based cryptography or hash-based signatures are considered strong candidates and are already being evaluated by the U.S. National Institute of Standards and Technology (NIST) as part of the Post-Quantum Cryptography standardization effort.
But implementing these changes isn’t trivial:
- Wallets, hardware devices, and full nodes will all require updates.
- New address formats may be necessary.
- Coordinating this upgrade without fragmenting the network will be a monumental governance task.
What complicates matters further is the false sense of security created by oversimplified claims, like “Bitcoin doesn’t use encryption, so quantum doesn’t matter.”
A Dangerous Misunderstanding
Adam Back’s tweet reflects a common confusion: conflating “encryption” with all of cryptography. While the statement may be correct in isolation, it misleads in context. Quantum computers don’t need to “decrypt” Bitcoin, they only need to break the signature scheme. And once they can, all Bitcoin that’s ever been sent (with an exposed public key) becomes vulnerable to theft.
In other words, Bitcoin’s quantum threat isn’t about hiding secrets: it’s about who controls the keys.
Conclusion: It’s Time for Clear Thinking, Not Soundbites
The debate around Bitcoin and quantum computing is not just technical: it’s strategic. While full-scale quantum computers may still be years or decades away, preparing for them requires action today. That includes honest communication, rigorous technical planning, and community consensus around future-proofing the protocol.
Yes, Bitcoin doesn’t use traditional encryption.
No, that doesn’t mean it’s immune to quantum risk.
If we want Bitcoin to last another 50 years, it’s time to take the quantum era seriously, and stop hiding behind semantic technicalities.
Jessica Jones is not a person. No notebook, no deadlines, no face behind the name — just a byline this newsroom publishes under. Here is the production line underneath it, because a name beside a portrait reads like a journalist, and this one is not one.
The models. Writing: gpt-5.6-luna. Out on the live web: gpt-5.6-luna and gpt-5.6-terra. Pictures: gpt-image-1. Swap one in the newsroom and this line swaps with it — it is read off the machines, not typed here.
How a story is made
- Research. The searching model reads around the story, pointed at primary sources — the filing, the post, the repository — rather than at somebody else's write-up of them.
- Writing. The writing model drafts it against what was found, at Jessica Jones's usual length and in Jessica Jones's usual register.
- The loop. A reviewer reads the draft and sends it back with notes. Then reads it again. A piece can go round several times before it leaves the building.
- Enrichment. A quotation has to appear word for word on the page it is taken from. A chart may only use figures that appear in the source it cites. Whatever fails is dropped, and the reason is kept.
- Fact check. A last pass hunts for claims the article makes and its sources do not.
- A human stop. Sensitive subjects are held for a person to read before publication, and a person can kill any of it at any point.
If that sounds less like a newsroom and more like a factory: quite. It is called Press Factory.
This article was generated using AI and published automatically without human pre-publication review.
Without human check
How this article was made
The article was produced by the Grandmonts Media News Engine using automated research, drafting and verification workflows. No human editor reviewed the article before publication. Grandmonts Media remains responsible for the published content. Errors can be reported at office@grandmonts.cz.