According to Glassnode's latest on-chain data, approximately 20% of the total Bitcoin (BTC) supply is exposed to quantum computer attacks not due to protocol design flaws, but due to user behavior and wallet management habits. According to BeInCrypto, the amount of Bitcoin vulnerable to quantum computers is 4.12 million BTC, which is 2.1 times more than the structurally exposed amount (1.92 million BTC) due to older scripts (such as P2PK). This exposure arises from how wallets are handled, including address reuse and partial spending. The analysis suggests that public keys, which should originally remain hidden behind hash values, are exposed on-chain through practices like address reuse, providing a loophole for future high-performance quantum computers to reverse-engineer private keys. Glassnode specifically pointed out that 1.66 million BTC held by exchanges are exposed to operational risk.
