Bitcoin is unlikely to face any meaningful threat from quantum computing for at least the next two to four decades, according to cryptographer and long-time cypherpunk Adam Back — one of the few people cited directly in the Bitcoin white paper.
Back responded to a question on X on Nov. 15 about whether Bitcoin is at risk from rapid advances in quantum computing. His answer was clear: “Probably not for 20–40 years.”
He added that the National Institute of Standards and Technology (NIST) has already approved post-quantum encryption standards that Bitcoin could adopt long before any “cryptographically relevant” quantum machines emerge.
Why the sudden concern?
The debate was reignited after a clip circulated of venture capitalist Chamath Palihapitiya, who claimed that quantum advances could make Bitcoin vulnerable in two to five years. He suggested that roughly 8,000 qubits could be enough to break SHA-256, the core hashing algorithm Bitcoin relies on.
But Back and other cryptographers say such estimates are not realistic when real-world quantum noise and engineering limits are taken into account.
Quantum computing today: high qubit counts, low real capability
Despite rapid research progress, current quantum machines are far from breaking modern cryptographic standards.
- Caltech’s neutral-atom quantum array currently holds the qubit-count record at 6,100 physical qubits.
But even this system can’t break RSA-2048, which theoretically requires just 4,000 logical qubits in a perfect noise-free environment. - Error-corrected logical qubits are the real bottleneck.
Quantinuum’s Helios, for example, reaches 98 physical qubits, which translates into 48 logical qubits — roughly 2 physical per 1 logical. - Universal systems like Atom Computing’s 1,180-qubit machine (the first to pass 1,000 qubits) also fall short of the error correction needed.
In other words, physical qubit count ≠ the ability to break Bitcoin’s cryptography.
Even optimistic experts believe the gap remains massive.
The real quantum issue: “Harvest now, decrypt later”
While Bitcoin itself is not currently exposed to quantum threats, one modern risk is the “harvest now, decrypt later” strategy.
In this attack, adversaries capture encrypted data today and store it until future quantum computers are powerful enough to decrypt it.
This threat impacts:
- governments
- corporations
- activists in authoritarian states
- anyone relying on long-term encrypted communications
But Bitcoin is structurally safer because:
- it uses cryptography to secure ownership, not private messaging
- it can upgrade to post-quantum standards before any actual threat arrives
- stolen historical blockchain data is useless without private keys
Zero-knowledge researcher Gianluca Di Bella told Cointelegraph that industries should begin transitioning to post-quantum standards now, noting that practical quantum systems could emerge in “10–15 years,” and that companies like Google or Microsoft may make breakthroughs even earlier.
Satoshi’s coins and the quantum question
Interestingly, Back noted in an earlier interview that quantum pressure could reveal whether Satoshi Nakamoto is still alive.
If quantum computers reached the point where old-style Bitcoin addresses became vulnerable, Satoshi would be forced to move his long-dormant coins to quantum-resistant addresses to protect them.
This hypothetical scenario remains distant — but is a reminder of how closely technology and Bitcoin’s origin story are intertwined.
- Bitcoin has no meaningful quantum threat for at least 20–40 years.
- Post-quantum standards already exist and can be integrated in time.
- Current quantum machines lack the error-corrected logical qubits needed to break Bitcoin.
- The real near-term issue is long-term encrypted data storage, not blockchain security.
If you want this in a non-AI detectable tone or in Cointelegraph style with subheadings, I can rewrite it.
Disclaimer
This content is for informational purposes only and does not constitute financial, investment, or legal advice. Cryptocurrency trading involves risk and may result in financial loss.