Measuring Bitcoin's Quantum-Exposed Supply

Crypto Insight Summary: Glassnode researchers Rafael Schultze-Kraft, Kilian Heeg, and CryptoVizArt published an analysis on May 20, 2026, quantifying Bitcoin's quantum-exposed supply by identifying coins whose public keys are already visible on-chain. They classify 6.04M BTC, or 30.2% of issued supply, as exposed at rest, while 13.99M BTC (69.8%) shows no public-key exposure. The exposure divides into structural sources (1.92M BTC, 9.6%), including early P2PK, P2MS, and modern Taproot (P2TR) outputs where public keys are visible by design, and operational sources (4.12M BTC, 20.6%), where address reuse, partial spending, or custody practices have revealed keys. Satoshi-era coins are flagged as the most persistent structural exposure, while BIP-360's proposed Pay-to-Merkle-Root (P2MR) is cited as a potential mitigation for Taproot's long-exposure issue. Exchange-related balances account for 1.66M BTC (8.3% of total supply), representing roughly 40% of all operationally unsafe BTC, with about half of labeled exchange balances susceptible compared to under 30% of non-exchange supply. Among major exchanges, Coinbase's labeled balances appear 5% exposed, while Binance and Bitfinex show 85% and Crypto Insight Analysis: Direction: Neutral Impact: Minor Impact Horizon: Long-term (1 quarter-1 year) Reasoning: Quantum exposure concerns are long-term but unlikely to impact market sentiment in the near term.