Bitcoin developers propose quantum‑resistant upgrade to protect billions in legacy wallets

Bitcoin developers are reviving a 2008 roadmap by Satoshi Nakamoto to defend the cryptocurrency against future quantum‑computing attacks. The new BIP‑360 and BIP‑361 proposals would introduce a migration to a quantum‑resistant address format (bc1z) based on Merkle‑tree cryptography and set a block‑height deadline that disables legacy Pay‑to‑PubKey (P2PK) addresses.

If the deadline passes, coins held in early‑era wallets that use the vulnerable ECDSA keys—estimated at about 35% of all mined Bitcoin, roughly 6.9 million BTC—could become inaccessible. The upgrades also include a recovery mechanism that would let users prove ownership of affected funds through alternative cryptographic proofs, allowing asset reclamation even after a hypothetical quantum breach.

The proposals reflect growing concern that advances in quantum algorithms such as Shor’s could eventually break the cryptographic foundations of Bitcoin, prompting a proactive shift to post‑quantum security standards.