Overview
- Glassnode published its on-chain analysis on May 21 and found about 6.04 million BTC, roughly 30.2% of issued supply, have had their public keys revealed and would be theoretically vulnerable to a future quantum-capable attack.
- The report splits exposed coins into structural exposure of about 1.92 million BTC that reveal keys by design and operational exposure of about 4.12 million BTC created by address reuse and poor change-output practices.
- Exchanges and custodial platforms account for roughly 1.66 million BTC of the operational exposure, with labeled balances showing large variation across firms from about 5% exposed at Coinbase to roughly 85% at Binance and 100% at some other venues.
- Glassnode and reporters stress that the most immediate way to cut measurable risk is operational: retiring used addresses, rotating keys, moving reserves to fresh wallets, and tightening custody controls.
- A full protocol-level move to quantum-resistant signatures would need years of coordinated work across developers, miners, wallets, custodians, standards bodies, and governments while the timing of a capable quantum 'Q‑Day' remains uncertain.