More than 7.12 million BTC, representing 35.4% of Bitcoin’s total supply, could face potential quantum computing vulnerabilities, according to blockchain analytics firm Glassnode. The findings highlight a long-term security challenge for Bitcoin, particularly for exchanges and early wallets holding coins with publicly exposed cryptographic keys.
35.4% of all #BTC (7.12M) has a visible public key, the part a future quantum computer could target.
25.8% of supply is exposed due to address reuse, 11.6% on exchanges. Moving those coins to a fresh address ends this exposure.
Charts now live in Studio: https://t.co/jN0cPT4I84 https://t.co/tAJd8jUOUU
— glassnode (@glassnode) November 10, 2026
Glassnode estimates that 25.8% of Bitcoin’s supply is exposed because of address reuse. Exchanges account for another significant portion, with 11.6% of the total supply held in exposed addresses.
Its entity-level data shows potential exposure of 100% for Robinhood, 85% for Binance and approximately 5% for Coinbase. US government holdings show no exposure. Glassnode clarified that these figures are not exchange security ratings.
Coinbase’s position is particularly relevant because it holds Bitcoin for most US spot ETFs. On October 29, its CEO confirmed that the company had started preparing its custody infrastructure for post-quantum security, stating, “We have begun the work to upgrade our custody to be post-quantum.”
The challenge is more complicated for Bitcoin associated with Satoshi Nakamoto. Ethereum Foundation researcher Justin Drake estimates that approximately 1 million BTC sits in early addresses linked to Bitcoin’s creator. These coins have remained unmoved for more than 15 years.
While holders can eliminate public-key exposure from reused addresses by transferring funds to fresh addresses, Satoshi’s dormant coins may be impossible to upgrade without access to their private keys.
Casa’s Jameson Lopp has proposed freezing coins that fail to migrate to quantum-resistant security. Blockstream CEO Adam Back, however, supports optional upgrades.
The potential financial exposure exceeds $500 billion at Bitcoin’s current market valuation. ARK Invest previously estimated more than $480 billion in exposed holdings, while CoinShares identified approximately 10,200 BTC as worth targeting for meaningful market impact.
Google said in March that a quantum computer with fewer than 500,000 qubits could potentially break the relevant encryption in minutes. However, no such machine currently exists. Back estimates that this capability could still be 20 to 40 years away.
Meanwhile, Nasdaq-listed Next Technology Holding approved selling or pledging approximately 5,833 BTC on October 30, citing quantum computing among other risks.
Jameson Lopp’s proposal and the separate BIP-360 draft have no activation date. Bitcoin’s challenge now extends beyond developing quantum-resistant cryptography to deciding how inaccessible and dormant coins should be treated.
