Quantum threat: 6 million BTC at risk, exchanges exposed

Glassnode finds 6.04M BTC—30% of supply—exposed to quantum risk due to visible public keys. Major exchanges hold most vulnerable coins. SegWit migration can reduce exposure.

Recent research from Glassnode shows that about 6.04 million BTC, or 30.2% of all issued Bitcoin, are currently at risk from potential quantum computing attacks. This vulnerability arises because their public keys are visible on-chain, making them susceptible to future quantum threats. The exposure is split into two categories: structural risk, which comes from early Bitcoin addresses and some modern outputs, and operational risk, mainly caused by address reuse and how exchanges store funds. Notably, exchanges like Binance and Bitfinex have 85% and 100% of their holdings exposed, respectively, while Coinbase has only 5% at risk. Glassnode suggests that migrating funds to SegWit addresses, which keep public keys hidden until coins are spent, can help reduce this risk. The quantum threat has already prompted some movement of long-dormant coins, such as a recent transfer of 500 BTC inactive for over a decade. This analysis offers one of the most detailed looks at Bitcoin’s quantum vulnerability to date.