Post-Quantum Cryptography (PQC)
Definition
Algorithms designed to resist attacks by sufficiently capable quantum computers. NIST standardised CRYSTALS-Kyber as ML-KEM and CRYSTALS-Dilithium as ML-DSA in 2024.
- Threat addressed
- Sufficiently capable quantum computers
- NIST standard
- ML-KEM (from CRYSTALS-Kyber)
- NIST standard 2
- ML-DSA (from CRYSTALS-Dilithium)
- Standardised
- 2024
Common questions
Why does PQC matter to digital forensics before large-scale quantum computers exist?+
Encrypted traffic and stored data captured today can be retained and decrypted later once quantum computers mature, a strategy known as harvest-now-decrypt-later, so investigators and defenders both need to account for confidentiality that may not hold in the future even though it holds now.
What kind of cryptography is PQC meant to replace?+
It targets algorithms whose security relies on problems a quantum computer can solve efficiently, chiefly RSA and elliptic-curve cryptography, both of which are broken in principle by Shor's algorithm on a sufficiently powerful quantum machine; symmetric ciphers like AES are far less affected and mainly need larger key sizes.
Related terms
- Brute Force
- Exhaustive search over the key space. The benchmark every other attack must beat. AES-128 brute force is computationally infeasible on classical hardware;...
- Cryptanalysis
- The study of breaking cryptographic systems. Complement to cryptography. Goals include recovering the key, recovering the plaintext, or distinguishing a cipher's output...
- Diffie-Hellman
- Key exchange protocol by Diffie, Hellman and Merkle (1976) that lets two parties agree on a shared secret over a public channel....
- Padding Oracle
- An attack that uses an error-message distinction (or a timing distinction) between 'padding invalid' and 'authentication invalid' to recover plaintext from CBC-mode...
- Perfect Forward Secrecy (PFS)
- Property of a key exchange where compromise of a long-term private key does not let the attacker decrypt past sessions. Achieved by...
- Side-Channel Attack
- Attack that exploits information leaked by a correct implementation: timing, power consumption, electromagnetic emanation, cache state, acoustic noise. Independent of the algebra...