An analysis says public keys are exposed for 7.12 million BTC, or 35.4 percent of Bitcoin's total supply. It is not at a level that can be decrypted now, but it could become a target if sufficiently powerful quantum computers emerge.

CoinPost, a blockchain media outlet, reported on the 11th that on-chain analytics firm Glassnode published the estimate on X, formerly Twitter.

Bitcoin with exposed public keys could face the risk of theft if a high-performance quantum computer emerges and private keys can be derived. Current quantum computers, however, do not have the performance needed for actual decryption. Google estimated in March that fewer than 500,000 qubits would be required to crack Bitcoin signature cryptography.

Glassnode pointed to address reuse as a main cause of public-key exposure. It said 25.8 percent of total supply had public keys revealed due to address reuse, and that exposure was also confirmed in exchange holdings. Exchange-held amounts were tallied at 11.6 percent of total supply. Glassnode suggested moving coins exposed by address reuse to a new address as a countermeasure.

The industry is also continuing discussions to prepare for the quantum computing threat. Coinbase proposed a draft discussion outline on Oct. 13 for a transition to a quantum-resistant system. It said a comprehensive strategy is needed that can protect even funds whose public keys are already exposed. It also stressed the need to prepare before quantum computers capable of decryption emerge, as changes to consensus rules and an industry transition could take years.

Bitcoin Core developer Cory Fields (코어리 필즈) also proposed three measures on the 5th to deter theft using quantum computers. All three would require bitcoin collateral equal to the transfer amount when moving funds from existing address formats after quantum attacks become possible. Because it would be difficult to distinguish legitimate owners from attackers, the idea is to require collateral from anyone moving funds.

The core of this discussion is that it quantified the exposed-public-key segment and set response priorities, even though the quantum computing threat has not yet materialised. Public-key exposure does not directly lead to theft, but analysis that potential targets exceed one-third of total supply is highlighting the need for address management and protocol-level responses.

35.4% of all #BTC (7.12M) has a visible public key, the part a future quantum computer could target. 25.8% of supply is exposed due to address reuse, 11.6% on exchanges. Moving those coins to a fresh address ends this exposure. Charts now live in Studio: https://t.co/jN0cPT4I84 https://t.co/tAJd8jUOUU