More than 6 million bitcoin are now held behind public keys visible on the blockchain, raising concerns about exposure as experts warn that artificial intelligence or quantum computing advances could threaten the security of digital assets.
Growing public-key exposure on the Bitcoin network
Data from Glassnode, a leading blockchain analytics firm, shows that this exposed supply represents 31.2% of Bitcoin’s circulating supply. This figure is 5 to 6 percentage points above the lowest level recorded in 2023.
Between May and the latest update, exposed bitcoin holdings increased by 222,000 BTC, now valued at $18.2 billion. In contrast, the total bitcoin supply grew by just 64,000 BTC during the same period, according to Rafael Schultze-Kraft, co-founder of Glassnode.
Exchanges have contributed significantly to this rise, accounting for 123,000 BTC of the newly exposed balance. Presently, exchanges hold 1.79 million BTC behind public keys that are viewable on-chain.
The degree of exposure varies across exchanges. Coinbase, a prominent U.S.-based crypto exchange, has 10% of its bitcoin exposed, while Binance’s share stands much higher at 83%.
| Entity | BTC Exposed (%) | Approximate Exposed BTC |
|---|---|---|
| Binance | 83% | Not specified |
| Coinbase | 10% | Not specified |
| Fidelity | 2% | 375,000 total BTC held |
| Grayscale | 49% | Not specified |
| Revolut | 99% | Not specified |
| Robinhood | 100% | Not specified |
Institutional holders show differing levels of exposure. Fidelity, the global financial services corporation, holds 375,000 BTC, of which only 2% are publicly exposed. Grayscale, an investment management firm specializing in digital currencies, has 49% of its holdings exposed, while digital platforms Revolut and Robinhood show exposure levels of 99% and 100% respectively. Holdings by the U.S., U.K., and El Salvador governments reportedly have no exposure under this analysis.
Mini dictionary: Glassnode is a blockchain analytics company that provides data insights and metrics related to on-chain activity, helping traders, investors, and institutions analyze cryptocurrency networks.
Security implications and technical outlook
Public keys become visible on the blockchain for several reasons, including address reuse or their appearance in special bitcoin output types like early pay-to-public-key transactions or Taproot-enabled outputs. If an attacker could exploit a future breakthrough in quantum computing or cryptanalysis, they might potentially derive private keys from these public keys, threatening the security of assets held in such wallets.
Although no practical attack on bitcoin’s or ether’s cryptographic security has been demonstrated to date, experts continue to monitor the situation closely, with a particular focus on developments in quantum computing and machine learning fields.
Ethereum researcher Justin Drake recently cautioned that the crypto industry should prepare for a scenario he called “bunker mode.” He warned of a theoretical possibility that advances in AI could rapidly enable shortcuts to breaking wallet cryptography.
Justin Drake has highlighted the urgent need for market participants to be prepared for worst-case scenarios, noting that AI could discover vulnerabilities in wallet encryption methods far faster than expected.
Drake also argued that institutions may face greater challenges adapting to emergency security measures than individual crypto holders, should an accelerated threat materialize.
Despite rising exposure figures, analysts specify that these metrics reflect addresses and not immediate risks, as no security compromises have been observed at this stage.
