Glassnode says roughly 30% of Bitcoin's supply is exposed to quantum risk because the public keys behind those coins are already visible on-chain, with most of that exposure tied to address r
Glassnode says roughly 30% of Bitcoin's supply is exposed to quantum risk because the public keys behind those coins are already visible on-chain, with most of that exposure tied to address reuse, partial spending, and custody behavior rather than the network as a whole.
In a new report, Glassnode measured 6.04 million BTC, equal to 30.2% of issued supply, sitting in addresses whose public keys are already revealed on the blockchain, according to its quantum-exposure analysis. That is the figure driving the roughly 30% headline. For related coverage, see Bitcoin ETF Outflows Accelerate as Risk Assets Face Broad Sell-Off.
Quantum-exposed Bitcoin supply 6.04M BTC (30.2%) Glassnode attributes this to already-visible public keys on-chain.The remaining 13.99 million BTC, or 69.8% of issued supply, shows no public-key exposure at rest under the same framework. That majority of coins keeps its public keys hidden until they are next spent. For related coverage, see Bitcoin steadies as implied vol eases, ETF inflows persist.
The estimate matters because it converts a long-running theoretical worry into a supply figure. A quantum computer capable of breaking elliptic-curve cryptography could, in principle, derive a private key from an exposed public key, and Glassnode's work quantifies how much of the supply currently sits in that state. For related coverage, see Bitcoin steadies as funding negative after Iran strikes.
Crucially, the roughly 30% figure is not attributable to address reuse alone. Glassnode splits the exposed supply into two buckets: 1.92 million BTC of structural exposure, equal to 9.6% of issued supply, driven by script design such as the oldest pay-to-public-key formats.
The larger share is operational exposure, which Glassnode puts at 4.12 million BTC, or 20.6% of supply, and links to address reuse, partial spending, and custody behavior rather than script design. That is the portion most directly connected to how holders actually use their wallets.
Operational quantum exposure 4.12M BTC (20.6%) This is the portion Glassnode links to address reuse, partial spending, and custody behavior rather than structural script design.This is where headline framing can mislead. Reporting that pins the full 30.2% on address reuse overstates the mechanism; only the 20.6% operational slice falls in that category, while the 9.6% structural slice is a function of the address type itself.
Address reuse simply means receiving new funds at the same Bitcoin address that has already been used to send coins. Because a spend reveals the address's public key, any balance sent back to that address afterward is exposed at rest.
A supporting academic framework backs the same logic. An arXiv paper on quantum exposure states that a coin is quantum-exposed exactly when its public key is visible on the blockchain, and notes that address reuse leaves any remaining or future balance exposed after the first spend.
That is why wallet behavior, not just the underlying script, shapes the risk. A holder who never reuses an address keeps the public key concealed until a spend, while repeated reuse leaves the key sitting in the open for anyone, or any future machine, to analyze.
For holders, the practical takeaway is wallet hygiene: using fresh addresses for each receive and avoiding reuse limits how much of a balance is exposed at rest. Custody providers face the same question at scale, since aggregated exchange balances contribute to the operational bucket.
The framing also feeds an ongoing security conversation rather than a price event. Developers are weighing migration paths such as the BIP-360 proposal for quantum-resistant outputs, a technical response that sits alongside this measurement rather than a live regulatory trigger.
Market conditions stayed subdued as the discussion circulated, with Bitcoin trading near $64,615 and the Fear & Greed Index reading 26, or Fear. The quantum framing has not translated into visible price action, echoing recent stretches when Bitcoin tested resistance as ETF flows cooled.
The debate lands during a cautious tape, with attention still on flows after Bitcoin ETF outflows accelerated alongside a broad risk-asset sell-off and holders absorbing billions in realized losses amid volatility. Against that backdrop, Glassnode's number reads as a long-horizon resilience metric, not an imminent-attack warning.
Disclaimer: This article is for informational purposes only and does not constitute financial or investment advice. Cryptocurrency and digital asset markets carry significant risk. Always do your own research before making decisions.
Bitcoininfonews first published the article titled Glassnode: Address Reuse Leaves 30% of Bitcoin Supply Exposed to Quantum Risk.
