Over 6 Million Bitcoin Sit Behind Exposed Public Keys as AI Warnings Grow

More than 6 million bitcoin, or 31.2% of circulating supply, now sit behind public keys that are already visible onchain. That is roughly 5 to 6 percentage points above the 2023 low, based on Glassnode data. Co-founder Rafael Schultze Kraft said exposed supply has grown by 222,000 BTC, worth about $18.2 billion, since the firm’s May report, while total supply rose by only 64,000 BTC. Exchanges account for 123,000 BTC of the increase and now hold 1.79 million BTC behind visible keys.

Exposure Levels Across Exchanges and Institutions

The gap between custodians is wide. Coinbase’s exposed share is 10%, against 83% at Binance. Fidelity holds about 375,000 BTC with just 2% exposed, while Grayscale stands at 49%, Revolut at 99% and Robinhood at 100%. Under this method, US, UK and El Salvador government holdings show no exposure.

How Public Keys Become Visible and Why It Matters

Keys can be revealed through address reuse or directly in certain output types, such as early pay-to-public-key outputs and Taproot. A powerful enough quantum computer, or a mathematical breakthrough, could let an attacker derive the matching private keys. The data arrives as Justin Drake urges the industry to prepare for “bunker mode,” warning that AI could find a shortcut to breaking wallet cryptography “in months, not years” in a worst-case scenario, before quantum computers arrive.