Adam Back Disputes Google's Quantum Threat Paper on Bitcoin

Bitcoin's chief cryptographer Adam Back has pushed back against Google's recent paper on the potential threat of quantum computers to Bitcoin. According to the paper, a vulnerability in Bitcoin's Schnorr signatures made them susceptible to quantum attacks. However, Back claims that this assessment is premature and that the Taproot upgrade, activated in 2021, already includes a mechanism for switching to post-quantum cryptography if needed.

Back pointed out that the Google paper confuses the relationship between Taproot and Schnorr signatures, stating that 'Taproot/Schnorr' are confused. He argued that even if quantum computers eventually break Bitcoin's current signature system, there is already a built-in pathway in the protocol to switch to a quantum-safe alternative without losing access to funds.

Back cited an academic proof by Tim Ruffing, which mathematically demonstrated that Taproot's commitment scheme is post-quantum secure. He warned against rushing new cryptography into Bitcoin, pointing out that premature fixes might pose greater risks than the quantum threat itself.