ISI, R.C. ATHENA ISI, R.C. ATHENA ISI, R.C. ATHENA ISI, R.C. ATHENA This document specifies extensions to the Ephemeral Diffie-Hellman over COSE (EDHOC) protocol to provide resistance against quantum computer adversaries by incorporating Post-Quantum Cryptography (PQC) mechanisms for both key exchange and authentication. It defines a Key Encapsulation Mechanism (KEM)-based authentication method to enable signature-free post-quantum authentication when PQC KEMs, such as NIST-standardized ML-KEM, are used. The document further describes scenarios where both parties employ KEM-based authentication, as well as cases where authentication methods are combined, with one party using KEM-based authentication and the other relying on a PQC signature scheme.