Glassnode
Reused Bitcoin addresses now hold 4.33M BTC, up from 3.79M a year ago, covering roughly 21.5% of circulating supply. Each reuse exposes the address's public key on-chain. Until coins move from an address, the key sits behind a hash; every subsequent spend from the same address broadcasts it permanently.
The exposure matters because reused addresses are the bucket a future quantum decryption event would target first. A quantum computer running Shor's algorithm against a published public key could derive the private key and walk away with any remaining balance at that address. The at-risk set has been growing for twelve straight months.
Frequently asked questions
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Why does Bitcoin address reuse expose public keys?
Until an address is spent from for the first time, its public key is hidden behind a hash. Once it is spent from, the public key is broadcast on-chain and stays visible permanently, and reusing the address stacks more exposure on the same key.
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How much Bitcoin sits in reused addresses today?
Roughly 4.33M BTC, up from 3.79M a year ago and now around 21.5% of circulating supply.
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Why is an exposed public key a quantum-computing risk?
A sufficiently powerful quantum computer running Shor's algorithm against a published public key could derive the private key and walk away with any remaining balance at that address.
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Does address reuse hurt Bitcoin privacy in the present tense?
Yes. Reused addresses let chain analysts cluster transactions into single wallets, eroding the pseudonymity the network is supposed to provide.
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What can a holder do to reduce address-reuse exposure?
Moving funds to a fresh, never-spent address hides the public key behind a hash again, removing the address from the at-risk set.
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