Glassnode: 30% of Bitcoin Exposes Keys to Quantum Risk

Blockchain analytics firm Glassnode published an analysis Wednesday finding that 30.2% of Bitcoin, about 6.04 million BTC valued at roughly $469 billion at current prices, has public cryptographic keys exposed on-chain. Those coins would be theoretically vulnerable if a quantum computer capable of breaking Bitcoin’s elliptic curve signatures were built.

The report splits exposed supply into structural and operational categories. Structural exposure totals 1.92 million BTC, or 9.6% of issued supply. Those coins sit in script formats that reveal public keys by design, including early pay-to-public-key outputs, legacy multisignature arrangements and some Taproot outputs. A number of structurally exposed coins appear dormant or lost and may not be movable.

Operational exposure amounts to 4.12 million BTC, or 20.6% of the supply. That exposure results from address reuse: when a wallet reuses an address and later spends from it, the transaction discloses the public key and any remaining balance becomes visible on-chain. Exchange-related holdings account for about 1.66 million BTC, equal to 8.3% of issued supply and roughly 40% of operational exposure. Glassnode’s labeled balances show wide variation by platform, with some exchange balances roughly 5% exposed while others register about 85% and 100% exposed in the firm’s data.

The analysis does not treat exposed balances as indicators of insolvency. Sovereign holdings included in Glassnode’s dataset for the United States, the United Kingdom and El Salvador show no public-key exposure.

Glassnode outlines measures custodians and exchanges can take to reduce visible exposure, including improved address management, reduced key reuse, tighter reserve handling and targeted migration planning. The Bitcoin developer community is discussing protocol-level responses, including a proposal called BIP-360 to introduce more quantum-resistant transaction formats and other proposals that would require migration or freezing of older coins by set deadlines.

Estimates for when a quantum computer could break the elliptic curve cryptography used by Bitcoin-often called Q-Day-generally fall in the early 2030s, though projections vary. Governments and private firms are increasing investment in quantum research; the United States has announced more than $2 billion in planned funding for quantum startups and foundries.

Glassnode presents the report as a baseline to help custodians and developers measure and reduce on-chain public-key exposure ahead of any future advances in quantum computing.