Post-quantum Key Encapsulation with ML-KEM in Public Key Cryptography for Initial Authentication in Kerberos (PKINIT)
This document specifies extensions to the Kerberos PKINIT pre-authentication mechanism to support post-quantum key establishment using the Module-Lattice-Based Key-Encapsulation Mechanism (ML-KEM) algorithms defined in . The extensions define a new kemInfo arm in PA-PK-AS-REP , a KDCKEMInfo structure signed by the KDC, HKDF-based AS reply key derivation (HKDF-SHA-512 for ML-KEM), downgrade-prevention rules, and a PAChecksum2 extension providing checksum algorithm agility in PKAuthenticator . The KEM path framework supports multiple KEM algorithms including ML-KEM, composite ML-KEM algorithms, and future KEM standards.




