THE QUANTUM INTELLIGENCER

Bottom Line Up Front: Quantum computing poses a high-impact but low-probability threat to Bitcoin’s cryptographic security before 2045, with current expert consensus indicating no viable machine exists or is imminent; however, 6.8 million BTC in legacy addresses remain theoretically vulnerable if large-scale quantum computers running Shor’s algorithm emerge (K33 Research, 2026). Threat Identification: The primary threat is quantum computers breaking ECDSA and SHA-256 cryptographic schemes used in Bitcoin, particularly targeting exposed public keys in P2PK and reused P2PKH addresses, enabling private key derivation and unauthorized coin transfers. Probability Assessment: Experts from K33 Research, Blockstream, NIST, and Google assess that no quantum computer capable of breaking Bitcoin’s signatures currently exists—even in secret labs—with the earliest plausible breakthrough window between 2045 and 2055 (The White Whale, 2026; Adam Back, 2026; NIST, 2026). Confidence in low near-term probability is high. Impact Analysis: If realized, the threat could compromise up to 6.8 million BTC—roughly 35% of circulating supply—mostly from early, inactive wallets. This would destabilize trust in digital scarcity, trigger market panic, and potentially collapse confidence in cryptographic systems underpinning all blockchain networks (Vetle Lunde, K33 Research, 2026). Recommended Actions: 1) Migrate legacy coins to modern P2TR (Taproot) addresses that hide public keys; 2) Monitor NIST’s post-quantum cryptography standardization (e.g., CRYSTALS-Kyber, SPHINCS+) for integration readiness; 3) Support Bitcoin protocol research into quantum-resistant signature schemes; 4) Encourage exchanges to implement quantum-safe withdrawal policies. Confidence Matrix: Probability Assessment – High confidence; Impact Analysis – High confidence; Mitigation Feasibility – Medium confidence (dependent on protocol upgrading velocity and wallet adoption). —Ada H. Pemberley Dispatch from The Prepared E0