Ledger CTO Charles Guillemet challenged the view that only about 30% of Bitcoin faces quantum-computing risk, while the remaining 70% is protected because its public keys are hidden behind hashes. Glassnode previously measured roughly 30.2% of BTC with spending public keys exposed on-chain, but Guillemet said that figure captures only the blockchain's static state. Public keys may also be present in xpub (extended public key for deriving addresses), devices, PSBTs, logs and backups. In addition, initiating a Bitcoin transaction reveals the public key before the transaction is confirmed. Citing Google Quantum AI research, Guillemet said a hypothetical high-speed quantum computer, which does not currently exist, could attack secp256k1 (elliptic curve used by Bitcoin signatures) in about nine minutes. He said concealing public keys alone cannot resolve the threat and that Bitcoin will ultimately need to migrate to post-quantum cryptography (cryptography designed to resist quantum computers).