Question 1

What is ML-KEM and what FIPS standard covers it?

Accepted Answer

ML-KEM (Module-Lattice Key Encapsulation Mechanism) is standardized in FIPS 203, published August 2024. It is a lattice-based KEM that replaces RSA and ECDH for key exchange, offering three parameter sets: ML-KEM-512 (Level 1), ML-KEM-768 (Level 3), and ML-KEM-1024 (Level 5).

Question 2

What is the recommended PQC replacement for RSA-2048?

Accepted Answer

For key exchange, ML-KEM-768 (FIPS 203, NIST Level 3) replaces RSA key transport. For digital signatures, ML-DSA-65 (FIPS 204, NIST Level 3) replaces RSA-2048 signing. Both provide equivalent or higher security against quantum attacks.

Question 3

What is the difference between ML-DSA and SLH-DSA?

Accepted Answer

ML-DSA (FIPS 204) is lattice-based with compact signatures (~2.4-4.6 KB) and fast verification, making it the primary choice. SLH-DSA (FIPS 205) is hash-based with larger signatures (~7-50 KB) but relies only on hash function security, serving as a conservative fallback if lattice assumptions are broken.

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