(September 29, 2023)

Such an all-conquering computer doesn’t actually exist yet. But there lies the paradox of what’s called quantum-resistant or “post-quantum” encryption: You don’t need a quantum computer to start laying the foundations for a quantum-powered hack — or, fortunately, to start building a defense.

The threat is a tactic called “collect now, decrypt later.” Well-heeled foreign intelligence agencies (and the American NSA) already scoop up terabytes of encrypted communication. Whatever they can’t crack today can just go into long-term storage, waiting for quantum computers to get powerful enough to break them.