Glassnode says 7.12 million BTC, or 35.4% of issued coins, sits behind a visible public key that a future quantum computer could target. Address reuse drives most of the exposure, while Bitcoin's quantum proposals remain drafts.
Bitcoin's publicly exposed supply has reached 7.12 million BTC, or 35.4% of issued coins, according to Glassnode. The figure renews discussion about which holdings a future quantum computer could target.
Glassnode said in its Nov. 10 X post that 25.8% of supply is exposed due to address reuse, including 11.6% held on exchanges. The exchange figure sits within the reuse category, so adding the two percentages would double-count part of the total.
Address reuse accounts for most exposure
Glassnode separates structural exposure, where an output reveals a public key by design, from operational exposure caused by how wallets handle funds. Reusing an address after spending can leave coins tied to a key already recorded on the blockchain.
According to Glassnode: "Moving those coins to a fresh address ends this exposure." The firm was referring to coins exposed through reuse.
An earlier May 20 snapshot put exposed holdings at 6.04 million BTC, or 30.2% of issued supply. The measure concerns keys visible while coins remain unspent, and it does not predict when a quantum attack might become possible.
Draft proposals target key hiding and signature replacement
BIP 360 proposes pay-to-Merkle-root outputs through a soft fork. It removes Taproot's key-path spending option while retaining script-tree functionality. Its authors say protection against faster attacks may require post-quantum signatures.
A separate draft, BIP 361, proposes migration away from legacy signatures after a post-quantum output type becomes available. Neither draft sets a migration deadline currently binding on holders.
Source: crypto.news
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