币界网报道：Quantum computing poses an imminent threat to blockchain security, with experts warning that Q-Day—when quantum computers can break current encryption—may arrive as early as 2025. IBM Quantum's Jay Gambetta notes that nation-states are already harvesting encrypted data for future decryption. BlackRock flagged quantum risks in its Bitcoin ETF filing, while researchers estimate 4M BTC (25% of circulating supply) could be stolen. Ethereum's Vitalik Buterin has proposed emergency hard forks, but transitioning to quantum-resistant blockchains may require years of downtime. Cybersecurity firm Quantum Defen5e warns RSA-2048 encryption could fall to under 1M qubits, with Google Quantum AI accelerating this timeline. Post-quantum cryptography upgrades are urgently