More than 6 million bitcoin now sit behind public keys that are already visible on-chain, a level that puts 31.2% of the circulating supply in that category, according to Glassnode data cited by CoinDesk.
The share is roughly 5 to 6 percentage points above the low reached in 2023. The figures have drawn fresh attention as warnings build around the possibility that advances in AI or quantum computing could one day weaken the cryptography used to secure bitcoin wallets.
Exposed supply rose by 222,000 BTC since May
Glassnode co-founder Rafael Schultze-Kraft said exposed supply has increased by 222,000 BTC since the firm’s May report, equal to about $18.2 billion based on the price cited in the article. Over the same stretch, total bitcoin supply grew by only 64,000 BTC.
Exchanges accounted for 123,000 BTC of that increase. They now hold 1.79 million BTC behind visible public keys.
Exposure levels differ widely across platforms and custodians
The proportions vary sharply depending on the institution.
- Coinbase has an exposed share of 10%
- Binance stands at 83%
- Fidelity holds about 375,000 BTC, with 2% exposed
- Grayscale is at 49%
- Revolut is at 99%
- Robinhood is at 100%
Under the same methodology, holdings attributed to the governments of the U.S., the U.K. and El Salvador show no exposure.
The metric tracks address usage, not an active exploit
CoinDesk noted that the figures measure address usage rather than immediate security risk. No practical attack on bitcoin or ether wallet keys has been demonstrated.
Public keys can become visible through address reuse, or they can appear directly in certain bitcoin output types, including early pay-to-public-key outputs and Taproot.
If a sufficiently capable quantum computer were developed, or if a mathematical breakthrough were to emerge, an attacker could theoretically derive the corresponding private keys from those exposed public keys.
Justin Drake calls for “bunker mode” preparations
The update came as Ethereum researcher Justin Drake urged the industry to prepare for “bunker mode.”
Drake said that in a worst-case scenario, AI could uncover a shortcut to breaking wallet cryptography “in months, not years,” potentially before quantum computers arrive.