Quantum Computing Hardware
Which is the most appropriate reason to hurry the migration to post-quantum cryptography even before large quantum computers exist?
- AQuantum computers of the mid-2020s are already routinely breaking RSA-2048
- BSwitching to post-quantum cryptography always makes communication faster
- CCiphertext intercepted and stored today may be decrypted by future quantum computers (“harvest now, decrypt later”), and migrating cryptography takes many years
Show answer and explanation
Answer: C. Ciphertext intercepted and stored today may be decrypted by future quantum computers (“harvest now, decrypt later”), and migrating cryptography takes many years
An attacker can record encrypted traffic now and, once quantum computers become practical, break the key exchange and read the contents. Information that must stay secret for a long time therefore needs to be protected with post-quantum cryptography even before quantum computers arrive. Cryptography is also built into operating systems, browsers, network equipment, smart cards and the firmware and hardware of embedded devices, and replacing all of it takes many years. Migration is being carried out step by step with hybrid schemes that combine conventional and post-quantum cryptography.
- A. As of the mid-2020s, no quantum computer that can break RSA-2048 exists.
- B. Many post-quantum schemes have larger keys or signatures, so they are not necessarily faster.
- C. Correct. The reasons are the risk that recorded ciphertext will be decrypted in the future and the time migration takes.