Will Quantum Computers Break Encryption? Separating Signal From Hype

This is the single most common question this firm receives from boards and general counsel, and it deserves a precise answer rather than a reassuring or alarming one.

The technical answer

Yes, in principle. A sufficiently large, sufficiently error-corrected quantum computer running Shor's algorithm could factor the large numbers underlying RSA encryption and solve the discrete logarithm problems underlying elliptic-curve cryptography — both foundational to most of today's internet security, from HTTPS to VPNs to digital signatures. No such machine exists today. Current quantum processors, even the most advanced publicly known systems, remain well short of the scale and error rates required to threaten production-grade encryption.

The timeline answer, and why it is the wrong question

Credible estimates for when a cryptographically relevant quantum computer might exist vary widely, often citing the 2030s, with meaningful uncertainty in both directions. But focusing solely on that date misses the operative risk: data with a long confidentiality shelf life — health records, trade secrets, government communications, financial infrastructure — can be intercepted and stored today, encrypted, for decryption once capable hardware exists. If your data needs to remain confidential for ten or twenty years, the relevant deadline is not 'when quantum computers arrive,' but 'today minus the years it would take an adversary to decrypt it once they arrive.'

What this means in practice

For most organisations, the right posture is neither panic nor complacency. It is a structured, risk-based migration: prioritise systems protecting long-lived sensitive data, follow the cryptographic standards being finalised by national and international standards bodies, and build contractual and governance flexibility so the transition can proceed in phases rather than as an emergency retrofit.