7.12 Million BTC Carry Visible Public Keys as Quantum Risk Rises

Roughly 7.12 million bitcoin — over a third of the issued supply — now sit at addresses with publicly visible public keys, according to on-chain analysis by Glassnode. The finding quantifies the share of Bitcoin's supply that a future quantum computer running Shor's algorithm could theoretically target, without establishing that any private key theft has occurred or that practical quantum attacks are imminent.

How much Bitcoin is exposed, and why?

Glassnode splits the exposure into two categories: structural and operational. Structural exposure comes from output types that reveal public keys by design. Early pay-to-public-key transactions and Taproot outputs both publish keys to the chain. May's analysis counted 1.92 million BTC in this structural group — coins whose keys are visible because of how the outputs were constructed, not because of user error.

Operational exposure is larger and behavioral. It arises when a transaction reveals a key that still controls unspent coins. If a user spends from an address once and later receives additional deposits there, the newly arrived coins link to an already-visible key. Wallet habits, not protocol design, create this risk.

What role does address reuse play?

Address reuse is the dominant driver. Glassnode's figures show reuse exposes 25.8% of Bitcoin's issued supply, including 11.6% held on exchanges. Exchange holdings sit inside the broader reuse figure, so summing the two percentages would double count coins held on reused exchange addresses.

Run against the 7.12 million exposed coins, reuse accounts for nearly 73% of all visible-key supply. Exchanges represent roughly 45% of that reused portion — a concentration that places custody platforms at the center of any remediation effort. The operational implication is direct: an exchange that consolidates deposits across a small set of hot-wallet addresses multiplies the coins tied to each visible key.

Can holders remove the exposure?

Yes, in the operational case. According to Glassnode, moving affected coins to fresh addresses removes the exposure caused by reuse. A transfer to a never-before-used address generates a new key that has not appeared on-chain, restoring the protection of the standard address-hash scheme, which does not reveal the public key until a spend occurs.

The structural group is harder to fix. Coins held in legacy pay-to-public-key outputs cannot un-reveal their keys; holders must move them to modern output types to eliminate the exposure, and doing so consumes the very key that is already visible. The remediation path exists but requires action from every holder of the 1.92 million BTC in this category, including presumed lost coins from Bitcoin's early years.

What does the analysis not claim?

Glassnode's findings establish neither private-key theft nor a timeline for practical quantum attacks. Shor's algorithm, run on a sufficiently powerful quantum computer, could recover the private keys corresponding to visible public keys. No such machine exists today at the required scale, and the report frames its numbers as a measurement of latent surface area rather than a prediction of loss.

The scale still matters for planning. A capture of even a fraction of 7.12 million BTC would dwarf every exchange hack on record, so migration timelines for custody infrastructure are becoming a governance question for exchanges and large treasuries rather than a purely technical one. Bitcoin's developer community continues to debate post-quantum address schemes, and any future soft fork would set the migration deadline that today's exposed holders are waiting on.