Bitcoin’s Quantum Defense Plan: What BIP-360 Actually Changes

Bitcoin Improvement Proposal 360 (BIP-360) formally places quantum resistance on Bitcoin's long-term roadmap by introducing Pay-to-Merkle-Root (P2MR). This proposal addresses the primary quantum threat vector: the exposure of public keys, which Shor's algorithm could exploit. P2MR is modeled after Taproot but critically removes the key path spending option, forcing all transactions through script paths that rely on hash-based commitments, thereby sharply reducing elliptic curve public key exposure. While this change preserves smart contract flexibility like multisig and timelocks via Tapscript Merkle trees, it does not automatically upgrade existing coins, nor does it replace current ECDSA/Schnorr signatures with new post-quantum schemes. The practical implication is that wallets will likely offer opt-in P2MR addresses for long-term holdings, though transactions may become slightly larger. Developers are acting now because critical infrastructure migrations take many years, emphasizing that BIP-360 is an incremental first step requiring ecosystem-wide coordination for full quantum resilience.

(Source：Cointelegraph)