Satoshi Nakamoto's estimated 1.1 million Bitcoin sits across approximately 22,000 Pay-to-Public-Key addresses of 50 BTC each, a legacy address format from Bitcoin's earliest days where the public key is directly visible on the blockchain. This makes these addresses among the most immediately vulnerable to a quantum attack because an attacker with a capable quantum computer would not need to wait for a transaction to reveal the public key. It is already exposed. The concentration of roughly 1.1 million BTC in these addresses, combined with Satoshi's decade-plus absence and the near-universal assumption that these coins will never move voluntarily, makes them a focal point for discussions about what a quantum attack on Bitcoin would look like in practice and what it would mean for the network.