Glassnode estimates that public keys are already visible for outputs holding 6.04 million BTC, or 30.2% of issued supply. The figure measures exposure under a specific future quantum-attack model. It does not show that those coins are currently compromised, and it does not predict when a machine capable of attacking Bitcoin signatures will exist.
What “exposed at rest” means
Bitcoin uses a private key to authorize spending and a corresponding public key to verify the signature. Today, deriving the private key from the public key is computationally impractical. The quantum concern is that a sufficiently capable cryptographic quantum computer could use Shor’s algorithm to recover a private key from a public one.
Glassnode therefore asks a narrow question: is the public key for an unspent coin already visible on-chain? If it is, the report classifies the coin as exposed at rest. If it is hidden behind a hash, the coin falls outside that group until a spend reveals the key. “Not exposed at rest” does not mean post-quantum secure under every scenario.
Two routes to public-key exposure
The report divides the 6.04 million BTC into structural and operational exposure. Structural exposure accounts for 1.92 million BTC, or 9.6% of issued supply. It includes output types that reveal a public key or equivalent by design, such as early pay-to-public-key outputs and Taproot outputs.
That classification needs care. Glassnode does not call Taproot broadly insecure. Taproot improves Bitcoin privacy and scripting, but its output key remains visible under the report’s at-rest quantum model. CryptoNeb’s quantum-defense overview covers proposals that separate today’s exposure map from possible signature and output changes.
Operational exposure is larger at 4.12 million BTC, or 20.6% of issued supply. It can arise when an output initially hides its public key, but address reuse, a partial spend or custody practices reveal the key while funds remain associated with it. Glassnode says this bucket is 2.1 times the structurally exposed balance.
What holders can take from the data
The 6.04 million figure is a stock measurement, not an estimate of coins that will be stolen. It also differs from on-spend exposure, where a public key becomes visible only after a transaction is broadcast. Any future migration plan would need to account for both cases, along with coins whose owners can no longer move them.
Users can reduce avoidable operational exposure by using wallets that generate fresh receive and change addresses, avoiding address reuse and keeping software current. Custodians have a broader task because reserve management and internal wallet structures can leave large balances tied to keys that have already appeared on-chain.
The report is best read as a baseline for tracking that visible-key set. Future measurements can show whether wallet practices and new output standards reduce operational exposure. They cannot supply a date for a practical quantum attack or establish that any named custodian is unsafe.
Adapted from Glassnode: 6.04 Million Bitcoin Have Public Keys Exposed – What It Means for Network Privacy.