Quantum Computing Hardware
Which correctly describes post-quantum cryptography (PQC)?
- ACryptography that runs on conventional computers and bases its security on mathematical problems (such as lattice problems) believed to be hard to solve efficiently even for quantum computers
- BCryptography that cannot encrypt or decrypt without using a quantum computer
- CCryptography that simply doubles the key length of RSA
Show answer and explanation
Answer: A. Cryptography that runs on conventional computers and bases its security on mathematical problems (such as lattice problems) believed to be hard to solve efficiently even for quantum computers
Post-quantum cryptography replaces factoring and the discrete logarithm problem, which Shor's algorithm can solve, with schemes based on lattice problems, hash functions and the like, and it runs as is on today's computers and network equipment. In 2024 the US NIST published standards including the lattice-based key encapsulation mechanism ML-KEM (FIPS 203) and the signature scheme ML-DSA (FIPS 204). Many of these schemes have larger keys or signatures than RSA or elliptic-curve cryptography, so migration proceeds with attention to the impact on communication protocols, embedded devices and hardware implementations. It is a different technology from quantum key distribution (QKD), which shares keys using quantum properties themselves.
- A. Correct. It is based on problems believed to be hard even for quantum computers and runs on conventional computers.
- B. This confuses it with quantum key distribution (QKD) and similar technologies. Post-quantum cryptography runs on ordinary computers.
- C. Shor's algorithm factors numbers in polynomial time, so making RSA keys longer is not a fundamental countermeasure.