Adam Back: Bitcoin Unlikely to Face Significant Quantum Threat for 20–40 Years
Adam Back, a prominent figure in the Bitcoin community, has stated that Bitcoin is unlikely to encounter a meaningful threat from quantum computing for the next 20 to 40 years. This contrasts with other perspectives; for instance, Chamath Palihapitiya has warned the timeline could be as short as 2 to 5 years. The current capability of quantum hardware remains insufficient to compromise Bitcoin's security. Systems such as Caltech's neutral-atom quantum processor and Quantinuum Helios currently operate with thousands or dozens of qubits but require heavy error correction, while Shor’s algorithm demands thousands of logical qubits to break RSA-2048 or Bitcoin’s elliptic-curve signatures. Present quantum computers are far from achieving this threshold.
To prepare for the eventual emergence of quantum threats, the National Institute of Standards and Technology (NIST) has approved post-quantum cryptographic standards, including SLH-DSA, which Bitcoin could adopt before quantum computers threaten its SHA-256 hashing algorithm. Jameson Lopp has proposed Bitcoin Improvement Proposal 360, outlining a multi-year transition toward quantum-resistant ML-DSA signatures expected to be selected by NIST in 2024.
While "harvest-now, decrypt-later"—the recording of encrypted data for future decryption—remains a theoretical concern, it is not yet a practical threat to Bitcoin ownership. Nonetheless, this possibility motivates the community to pursue timely protocol upgrades.
In practical terms, some entities are already taking steps to reduce quantum risk exposure. El Salvador reportedly holds more than 6,000 BTC and has distributed its treasury across 14 addresses, while analysts estimate between 6 to 7 million BTC remain in older address formats potentially vulnerable to future quantum attacks. Projects such as Rootstock and Naoris Protocol are exploring post-quantum developments, and several hardware wallets like Trezor’s Safe 7 now offer paths to quantum-secure updates, helping to future-proof Bitcoin’s infrastructure.
