IETF RFC 9242 PDF

Abstract

This document defines a new exchange, called "Intermediate Exchange", for the Internet Key Exchange Protocol Version 2 (IKEv2). This exchange can be used for transferring large amounts of data in the process of IKEv2 Security Association (SA) establishment. An example of the need to do this is using key exchange methods resistant to Quantum Computers (QCs) for IKE SA establishment. The Intermediate Exchange makes it possible to use the existing IKE fragmentation mechanism (which cannot be used in the initial IKEv2 exchange), helping to avoid IP fragmentation of large IKE messages if they need to be sent before IKEv2 SA is established.