An Extension for EAP-Only Authentication in IKEv2
RFC 5998

Internet Engineering Task Force (IETF)                         P. Eronen
Request for Comments: 5998                                   Independent
Updates: 5996                                              H. Tschofenig
Category: Standards Track                         Nokia Siemens Networks
ISSN: 2070-1721                                               Y. Sheffer
                                                             Independent
                                                          September 2010

           An Extension for EAP-Only Authentication in IKEv2

Abstract

   IKEv2 specifies that Extensible Authentication Protocol (EAP)
   authentication must be used together with responder authentication
   based on public key signatures.  This is necessary with old EAP
   methods that provide only unilateral authentication using, e.g., one-
   time passwords or token cards.

   This document specifies how EAP methods that provide mutual
   authentication and key agreement can be used to provide extensible
   responder authentication for IKEv2 based on methods other than public
   key signatures.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5998.

Eronen, et al.               Standards Track                    [Page 1]
RFC 5998               Extension for EAP in IKEv2         September 2010

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1.  Introduction

   The Extensible Authentication Protocol (EAP), defined in [RFC3748],
   is an authentication framework that supports multiple authentication
   mechanisms.  Today, EAP has been implemented at end hosts and routers
   that connect via switched circuits or dial-up lines using PPP
   [RFC1661], IEEE 802 wired switches [IEEE8021X], and IEEE 802.11
   wireless access points [IEEE80211i].

   One of the advantages of the EAP architecture is its flexibility.
   EAP is used to select a specific authentication mechanism, typically
   after the authenticator requests more information in order to
   determine the specific authentication method to be used.  Rather than
   requiring the authenticator (e.g., wireless LAN access point) to be
   updated to support each new authentication method, EAP permits the
   use of a backend authentication server that may implement some or all
   authentication methods.

Eronen, et al.               Standards Track                    [Page 2]
RFC 5998               Extension for EAP in IKEv2         September 2010

   IKEv2 ([RFC4306] and [RFC5996]) is a component of IPsec used for
   performing mutual authentication and establishing and maintaining
   Security Associations (SAs) for IPsec ESP and Authentication Header
   (AH).  In addition to supporting authentication using public key
   signatures and shared secrets, IKEv2 also supports EAP
   authentication.

   IKEv2 provides EAP authentication since it was recognized that public
   key signatures and shared secrets are not flexible enough to meet the