One day soon, at a research lab near Santa Barbara or Seattle or a secret facility in the Chinese mountains, it will begin: the sudden unlocking of the world's secrets. Your secrets.

Cybersecurity analysts call this Q-Day - the day someone builds a quantum computer that can crack the most widely used forms of encryption. These math problems have kept humanity's intimate data safe for decades, but on Q-Day, everything could become vulnerable, for everyone: emails, text messages, anonymous posts, location histories, bitcoin wallets, police reports, hospital records, power stations, the entire global financial system.