Research highlights millions of Bitcoin exposed to future quantum computing risks

Recent research estimates that up to 6.9 million Bitcoin have public keys exposed on-chain, posing future quantum computing vulnerabilities. A targeted estimate found approximately 1.7 million BTC held across roughly 20,000 public keys in legacy pay-to-public-key outputs, which display public keys directly on-chain. This follows an earlier review identifying at least 4.83 million BTC, or 24.1% of unspent Bitcoin at block 959,193, exposed to quantum risks. Countermeasures under development include Bitcoin Improvement Proposal 361, BitGo's risk-scoring wallet controls, and work by the Quantum Alliance.