Quantum Computing and Post-Quantum Migration

Quantum computers use fundamentally different physics than the computers you use every day. A sufficiently powerful quantum computer could, in theory, solve certain math problems much faster than any classical computer — including some of the exact problems that today's widely used public-key encryption (like RSA, which you saw back in Course 5) relies on being hard to solve.

*Reality check: today's quantum computers are not yet powerful enough to break modern encryption in practice. This is a forward-looking planning problem, not an active, immediate threat.

"Harvest Now, Decrypt Later"

The reason organizations are planning for this now, rather than waiting, is a concept called "harvest now, decrypt later." An attacker could record encrypted data today — even though they can't read it yet — and simply store it, hoping to decrypt it once quantum computers become powerful enough. Data that needs to stay confidential for many years is most at risk from this strategy.

Post-Quantum Migration

Post-quantum cryptography refers to new encryption algorithms designed to remain secure even against a future quantum computer. Post-quantum migration is the ongoing, gradual process of replacing today's algorithms with these newer ones before quantum computers become a practical threat — similar in spirit to how organizations gradually retired older, weaker encryption standards in the past.