Overview
- Two independent on-chain analysts report roughly 35.4–35.6% of Bitcoin supply—about 7.12 million BTC—has public keys visible on the blockchain, a sharp rise from about 24.8% in early 2021.
- Glassnode attributes the bulk of the exposure to address reuse (25.8%) and custody practices at exchanges (11.6%), while independent ChainQuery data closely matches Glassnode’s totals.
- Some exposed balances are structural and cannot be fixed by users: legacy pay-to-public-key outputs hold about 1.71 million BTC and Taproot-related outputs about 222,000 BTC.
- The immediate, practical mitigation is operational: move coins off reused addresses to freshly generated ones and direct new deposits to fresh addresses, while custody providers build tools to track and reduce exposure.
- Developers have circulated draft protocol responses—BIP 360 to hide keys using pay-to-Merkle-root outputs and BIP 361 to phase signature migration—yet no binding migration plan exists and no quantum computer today can execute the attack these measures defend against.