EU warns Q-Day could arrive before quantum computers are commercially viable

The European Union is preparing for a cybersecurity threat that sounds like a paradox: quantum computers might break modern encryption before they’re actually useful for anything else. The bloc’s NIS Cooperation Group has published a roadmap requiring all 27 member states to begin planning their transition to post-quantum cryptography by December 31, 2026. The core concern is what researchers call “Q-Day,” the moment a quantum computer becomes powerful enough to crack the asymmetric encryption that secures everything from banking systems to blockchain networks. The “store now, decrypt later” problem The most unsettling part of the EU’s warning isn’t about future attacks. It’s about attacks happening right now. The concept is straightforward: adversaries can harvest encrypted data today and simply wait until quantum hardware matures enough to decrypt it. By the time Q-Day actually arrives, years of sensitive communications, financial records, and government secrets could be cracked open retroactively. Recent technical advancements, including research from Google, have pushed some estimates for viable quantum attacks forward to as early as 2029. That’s notably ahead of when most expe...