Bitcoin security researcher Justin Drake warned that the approximately 1 million BTC mined by Satoshi Nakamoto across 20,000 addresses represent a primary target for a future quantum attack. These early addresses expose their raw public key without a hashing step, making them vulnerable, unlike BTC held in hashed addresses which remain protected until spent. Drake advises users to send change to a fresh address whenever they spend bitcoin to protect their public key. A proposal called BIP-361, published in April, would gradually freeze addresses considered vulnerable to quantum attacks. Analyst James Check estimates 1.716 million BTC as the truly exposed amount, lower than the 6.9 million figure often cited in broader discussions about exposed keys.
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