NIST finalized three post-quantum cryptography standards on August 13, 2024. The announcement grouped them under a broad encryption headline, but assigned them different jobs. FIPS 203 specifies ML-KEM. FIPS 204 specifies ML-DSA for digital signatures, while FIPS 205 specifies another signature algorithm, SLH-DSA. Three publications do not mean three interchangeable ways to perform the same task. [nist]

FIPS 203 supplies the more precise account of ML-KEM. A key-encapsulation mechanism allows two parties to establish a shared secret key over a public channel, under specified conditions. Symmetric-key algorithms can then use that secret for encryption or authentication. The mechanism establishes key material; it does not directly encrypt bulk application data such as a collection of documents. [fips203]

Digital signatures address a different requirement. NIST describes their use for identity authentication and identifies ML-DSA as its primary signature standard. SLH-DSA uses a different mathematical approach and is intended as a backup if ML-DSA proves vulnerable. A reader evaluating a claim about confidential communications therefore needs to distinguish key establishment from the signature function, rather than counting algorithm names. [nist][fips203]

Our interpretation is that a useful security claim should say which function is being supplied. Neither document demonstrates that a particular product or network has completed a transition. FIPS 203 expressly warns that conformance does not guarantee overall system security. This account uses the August 13 announcement and standard as complementary primary documents from NIST, not two independent assessments or a certification of a product. [nist][fips203]

Source documents

  1. NIST Releases First 3 Finalized Post-Quantum Encryption Standards | NISThttps://www.nist.gov/news-events/news/2024/08/nist-releases-first-3-finalized-post-quantum-encryption-standards
  2. Module-Lattice-Based Key-Encapsulation Mechanism Standard (FIPS 203)https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.203.pdf