Glassnode: Nearly A Third Of All Bitcoin Already Exposed To Quantum Risk

Blockchain analytics firm Glassnode has published new research quantifying the share of Bitcoin supply where public keys are already visible on-chain — the prerequisite for any future quantum computer attack.

More than 6 million Bitcoin — equivalent to 30.2% of all coins ever issued — are currently exposed to potential quantum computing attacks, according to new research from on-chain intelligence platform Glassnode. The analysis, which maps public-key visibility across the Bitcoin blockchain, represents one of the most detailed assessments to date of the network’s quantum vulnerability profile.

The research draws a precise technical line: a coin is considered “at risk” not when it is transacted, but when its associated public key is already visible on the blockchain while the funds remain unspent. A sufficiently advanced quantum computer running Shor’s algorithm could, in theory, derive a private key from a known public key — meaning exposure begins the moment that key becomes public, not when a transaction is broadcast.

Of the 6.04 million BTC classified as exposed, Glassnode separates the risk into two distinct categories. Structural exposure accounts for 1.92 million BTC (9.6% of supply), covering output types that reveal public keys by design — including early Pay-to-Public-Key outputs from Bitcoin’s founding era, legacy multisig structures, and modern Taproot outputs. Coins in this category are exposed regardless of how carefully their owners manage their wallets.

The larger and more actionable category is operational exposure, totalling 4.12 million BTC, or 20.6% of supply. These are coins that were initially protected behind cryptographic hashes but became exposed through address reuse, partial spending, or institutional custody practices that left public keys visible on-chain while balances remained in place. Critically, this form of exposure is largely preventable through better wallet hygiene.

Exchanges Account for 40% of Preventable Exposure — but Performance Varies Wildly

Exchanges sit at the centre of the operational exposure problem. Glassnode estimates that 1.63–1.66 million BTC held by exchange-related entities falls into the exposed category, representing roughly 40% of all operationally unsafe supply. The firm notes that approximately half of all labeled exchange-held Bitcoin is currently exposed — a significantly higher rate than non-exchange supply, where the figure sits below 30%.

The disparity between individual custodians is striking. Coinbase, according to the analysis, holds only around 5% of its labeled balances in exposed structures. Binance and Bitfinex, by contrast, show exposure rates of 85% and 100%, respectively. Among other entities, Robinhood and WisdomTree are fully exposed, while Fidelity and CashApp sit near 2%. Sovereign government holdings — including those of the United States, United Kingdom, and El Salvador — show essentially zero quantum exposure.

Glassnode is careful to frame its findings as a data baseline rather than an alarm. The report explicitly does not forecast when, or whether, quantum computers capable of breaking Bitcoin’s cryptography will exist, and makes no claims about the solvency or security of any named custodian. The exposure rates reflect observable on-chain footprints, not imminent threats.

The firm does, however, draw a clear operational conclusion: a substantial portion of Bitcoin’s quantum exposure is not a protocol-level problem waiting on a technical fix. It is a custody and address-management problem that active entities — exchanges, asset managers, and institutional custodians — could begin addressing today through standard practices such as avoiding key reuse and rotating change outputs.

For the portion of exposed supply tied to dormant or abandoned wallets, including coins potentially held by Bitcoin’s pseudonymous creator Satoshi Nakamoto, no such remedy is available. Those coins, Glassnode notes, may remain exposed indefinitely unless the Bitcoin network adopts broader protocol-level changes — a prospect the report describes as likely contentious.

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