According to Glassnode co-founder Rafael Schultze-Kraft, approximately **6.26 million BTC, representing 31.2% of Bitcoin’s circulating supply**, is held at addresses with publicly exposed cryptographic keys. These assets could face potential security risks as quantum computing technology advances.
In early 2021, the proportion stood at 24.8%, but it has now returned to levels last observed in 2016.
Address reuse is the primary reason for public key exposure, accounting for approximately 4.33 million BTC. Another 1.94 million BTC is exposed due to specific sсript types, including 1.71 million BTC held in P2PK addresses and 222,000 BTC associated with Taproot.
**Cryptocurrency exchanges represent a significant portion of the exposed supply.** Approximately 1.79 million BTC is held on exchange addresses with exposed public keys. The estimated proportions inсlude:
– Coinbase — 10%;
– Binance — 83%;
– Bitfinex — 100%;
– Grayscale — 49%;
– Revolut — 99%;
– Robinhood — 100%.
Overall, 57% of Bitcoin balances held on exchanges are associated with exposed public keys, compared with 55% in May and 39% in early 2021.
Researchers emphasize that **public key exposure does not mean funds have been compromised or are immediately at risk**. Instead, it represents a potential long-term security concern if future quantum computers become capable of breaking existing digital signature cryptography.
Schultze-Kraft also clarified that these figures should not be interpreted as an exchange security ranking or an assessment of any platform’s financial stability.
