Ledger CTO: Claim that only ~30% of BTC faces quantum risk is questionable

PANews, September 28 – Ledger CTO Charles Guillemet said he disagrees with the view that "only about 30% of BTC faces quantum computing risk, while the remaining ~70% is safe because it is protected by public key hashes." Glassnode data shows that about 30.2% of BTC currently has its spending public keys exposed on-chain, but Guillemet noted that this only reflects the on-chain resting state; unexposed public keys may still exist in xpubs, devices, PSBTs, logs, or backups. Moreover, once BTC initiates a transaction, the public key is made public before the transaction is confirmed.

Citing Google Quantum AI research, Guillemet said that under a high-speed quantum computer model that does not yet exist, relevant attacks against secp256k1 could be completed in about 9 minutes. Therefore, hiding public keys alone cannot solve the quantum risk, and Bitcoin will ultimately still need to migrate to post-quantum cryptography.