Bitcoin Won’t Face...

Bitcoin Won’t Face Quantum Threat for Decades, Says Adam Back

By José Oramas November 18, 2025 In Bitcoin, Quantum Computing

bitcoin and quantum computer in street city background. raise and fall bitcoin — Source:AdobeStock

Cryptographer Adam Back dismissed the imminent quantum computing threat to Bitcoin, estimating that “cryptographically relevant” machines are likely 20 to 40 years away.
This timeframe contrasts with warnings from some experts, like Chamath Palihapitiya, who suggest a threat window of just two to five years.
Back noted that the US NIST has already standardised post-quantum cryptographic schemes (like SLH-DSA) that Bitcoin can integrate over time to ensure it is quantum-ready.

Quantum computers, one of the most concerning topics in the crypto community, might not be the serious threat it’s categorised as, at least not for several decades, says cryptographer Adam Back.

According to Back, who is referenced in the original Bitcoin (BTC) white paper, BTC is unlikely to face a serious threat from quantum computers because “cryptographically relevant” machines could take up to 40 years.

He added that the US National Institute of Standards and Technology has already signed off on post-quantum cryptographic schemes that Bitcoin could integrate well before existing protections become breakable.

Probably not for 20-40 years, if then. And there are quantum secure signatures, NIST standardized SLH-DSA last year. Bitcoin can add over time, as the evaluation continues and be quantum ready, long before cryptographically relevant quantum computers arrive.

Adam Back, Cryptographer and CEO of Blockstream.

The exchange was triggered by a clip of venture capitalist Chamath Palihapitiya, who argued that quantum attacks on BTC could arrive within two to five years. In that video, Palihapitiya said a machine with around 8,000 error-corrected qubits could undermine SHA-256, the hash function securing the proof-of-work consensus.

Back’s view contrasts with that timeline, suggesting that the industry has decades to plan any migration to quantum-resistant signatures or hashing if the threat materialises.

Any Back-Up Plan?

There is progress being made, with efforts focused on developing and standardizing post-quantum cryptography (PQC) algorithms that are resistant to attacks from quantum computers – or ‘Big Scary Quantum Computers,’ as Bitcoin analyst Willy Woo calls them.

Talking about Woo, he recently suggested that a temporary solution to any potential quantum threats in the next 4-5 years is to just send your BTC into a SegWit wallet, and basically leave them there until the Bitcoin network adopts quantum-safe cryptography. And you also can’t spend it before that because you’d be exposing your public keys on-chain, defeating the purpose.