Bitcoin quantum threat: Which wallets face the most risk?

The report identifies older Bitcoin wallets that have exposed their public keys—especially early pay-to-public-key addresses and reused addresses—as most vulnerable to a future quantum attack. Funds in addresses whose public keys remain hidden behind hashes are less exposed until they spend, when the key becomes public. The threat is not an immediate risk with current quantum capabilities, but it underscores the need for post-quantum migration plans and careful handling of long-dormant coins.