This document specifies EAP-IKEv2, an Extensible Authentication Protocol (EAP) method that is based on the Internet Key Exchange (IKEv2) protocol. EAP-IKEv2 provides mutual authentication and session key establishment between an EAP peer and an EAP server. It supports authentication techniques that are based on passwords, high-entropy shared keys, and public key certificates. EAP-IKEv2 further provides support for cryptographic ciphersuite negotiation, hash function agility, identity confidentiality (in certain modes of operation), fragmentation, and an optional “fast reconnect” mode.