Quantum fixes protect Bitcoin, but legit owners risk lockout

Crypto investor Nic Carter's worst-case quantum scenario consists of a hostile actor recovering the keys to dormant Bitcoin, then broadcasting a wave of spends across 10 blocks.In his Oct. 13 interview with Luke Martin, Carter says early coins moving together could shake confidence in the network.The stakes extend beyond choosing stronger cryptography. Glassnode's May 20 analysis identified 6.04 million BTC, or 30.2% of then-issued supply, with public keys already exposed.The scenario assumes a future quantum machine capable of breaking Bitcoin's key cryptography. Google's published research models future resources for such an attack, and Bitcoin key recovery remains undemonstrated in that work. Large early outputs can nevertheless make a rapid transfer possible on block-space grounds.Can millions of BTC fit in 10 blocks?A sufficiently powerful quantum computer could use Shor's algorithm to recover private keys from exposed public keys, gaining the ability to authorize spending. Early pay-to-public-key (P2PK) outputs reveal those keys directly.An attacker could work privately, withholding transactions until ready, as Bitcoin Improvement Proposal 361 (BIP-361) explains.Bitcoin track...