Quantum Computers and Bitcoin: The Real Threat Is Not Code, but Consent

The Quantum Question: How Real Is the Threat to Bitcoin?

Quantum computing has for years been portrayed as Bitcoin's potential "ultimate enemy": the moment a quantum machine powerful enough arrives, it could theoretically crack the elliptic curve cryptography protecting millions of BTC.

The fear is not science fiction: Bitcoin still uses ECDSA for most addresses and Schnorr signatures for Taproot, both of which are vulnerable to a mature version of Shor's algorithm.

But here's the key point: the cryptographic tools needed to make Bitcoin resistant to quantum computers already exist. The US National Institute of Standards and Technology (NIST) approved several post-quantum schemes last year, and Bitcoin developers have proposed drafts such as BIP-360 to outline migration paths.

Technically, Bitcoin can adapt. Politically? That's where the real rift opens.

Analysts: Bitcoin's Politics Is the Major Problem

James Check, an on-chain analyst, argues that the quantum threat is "a consensus problem disguised as a crypto problem".

His point is simple: even if the network adopted quantum-resistant signatures, the problem would remain for old coins locked in vulnerable addresses.

And that's a huge amount of Bitcoin.

The data shows that:

• 32.4 per cent of all BTCs have not moved in five years
• 16.8 per cent have not moved in over ten years
• 8.2 per cent have been at a standstill for 7-10 years

Not all of these dormant coins are lost, but many belong to early adopters who no longer have access to the keys, or Satoshi Nakamoto himself. If a quantum computer were one day able to extract private keys from exposed public keys, trillions of dollars could suddenly pour into the market.

Ceteris Paribus of Delphi Digital makes this clear:

"Quantum-resistant Bitcoin will be possible, but it doesn't solve the problem of the old coins."

Adam Back, one of the early cypherpunks quoted by Satoshi, reiterated the dilemma: either those coins are deprecated, or they will be stolen. In other words, the problem is one of governance, not mathematics.

Post-Quantum Solutions Already Exist, But They Don't Protect Old Wallets

If the community decided to migrate, the new addresses could be updated quickly. But a backward-compatible solution that also protects historical wallets? According to many experts, it may never come.

Other blockchains, such as Sui, Solana, Cosmos and Near, have experimented with solutions that preserve old signatures through zero-knowledge testing. Bitcoin, however, does not have this cryptographic advantage: its curve does not allow the same approach.

This means that older addresses would remain vulnerable without a politically explosive hard fork.

Looking Ahead: The Countdown Is Social, Not Scientific

The estimates for the "quantum danger day" vary between 20 and 40 years, giving Bitcoin time, but no guarantees. The real countdown is about governance: will the community be able to coordinate a migration before quantum hardware makes a choice compulsory?

If not, the biggest shake-up in Bitcoin's history will not be caused by a machine, but by its inability to decide how to protect its past.