35% of Bitcoins are exposed to a quantum computer attack—can we protect ourselves from it today?

Glassnode estimates that 7.12 million BTC—about 35% of Bitcoin’s supply—is exposed to quantum computing risk because those coins’ public keys are already visible on-chain, largely due to address reuse. The finding matters because a sufficiently powerful quantum computer could derive private keys from exposed public keys, putting a significant share of Bitcoin’s market value at risk. Watch for wallet providers and protocols promoting address hygiene and post-quantum signature schemes, and for further Glassnode data breaking down how much of the exposure comes from reused addresses versus other on-chain patterns.