The IETF published RFC 8784 on June 30, 2020, defining an extension to the Internet Key Exchange Protocol Version 2 (IKEv2) that provides resistance to quantum computer attacks by mixing preshared keys into the key derivation process. The document was produced by the IP Security Maintenance and Extensions (IPSECME) Working Group and was published as a Proposed Standard.
RFC 8784 addresses the risk that an adversary could store VPN communications encrypted under IKEv2 today and decrypt them later using a quantum computer. The specification adds a post-quantum preshared key (PPK) as an additional input to the SK_d key derivation value, which generates key material for IPsec Security Associations and subsequent IKE SAs. According to the document, this approach provides quantum resistance to IPsec SAs while minimizing changes to the existing IKEv2 protocol.
Authored by Scott Fluhrer, Panos Kampanakis, and David McGrew of Cisco Systems, along with Valery Smyslov of ELVIS-PLUS, the specification preserves existing IKEv2 authentication and key exchange mechanisms. Classical Diffie-Hellman exchanges and public key infrastructure authentication remain in place, with the PPK serving as a parallel protection layer. The U.S. National Security Agency later referenced RFC 8784 in its Commercial Solutions for Classified post-quantum cryptography guidance.