Extensible Authentication Protocol - Generalized Pre-Shared Key (EAP-GPSK) Method
RFC 5433

Network Working Group                                          T. Clancy
Request for Comments: 5433                                           LTS
Category: Standards Track                                  H. Tschofenig
                                                  Nokia Siemens Networks
                                                           February 2009

                 Extensible Authentication Protocol -
              Generalized Pre-Shared Key (EAP-GPSK) Method

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Abstract

   This memo defines an Extensible Authentication Protocol (EAP) method
   called EAP Generalized Pre-Shared Key (EAP-GPSK).  This method is a
   lightweight shared-key authentication protocol supporting mutual
   authentication and key derivation.

Clancy & Tschofenig         Standards Track                     [Page 1]
RFC 5433                        EAP-GPSK                   February 2009

Table of Contents

   1. Introduction ....................................................3
   2. Terminology .....................................................4
   3. Overview ........................................................6
   4. Key Derivation ..................................................8
   5. Key Management .................................................11
   6. Ciphersuites ...................................................11
   7. Generalized Key Derivation Function (GKDF) .....................12
   8. Ciphersuites Processing Rules ..................................13
      8.1. Ciphersuite #1 ............................................13
           8.1.1. Encryption .........................................13
           8.1.2. Integrity ..........................................13
      8.2. Ciphersuite #2 ............................................14
           8.2.1. Encryption .........................................14
           8.2.2. Integrity ..........................................14
   9. Packet Formats .................................................15
      9.1. Header Format .............................................15
      9.2. Ciphersuite Formatting ....................................16
      9.3. Payload Formatting ........................................16
      9.4. Protected Data ............................................21
   10. Packet Processing Rules .......................................24
   11. Example Message Exchanges .....................................25
   12. Security Considerations .......................................28
      12.1. Security Claims ..........................................28
      12.2. Mutual Authentication ....................................29
      12.3. Protected Result Indications .............................29
      12.4. Integrity Protection .....................................29
      12.5. Replay Protection ........................................30
      12.6. Reflection Attacks .......................................30
      12.7. Dictionary Attacks .......................................30
      12.8. Key Derivation and Key Strength ..........................31
      12.9. Denial-of-Service Resistance .............................31
      12.10. Session Independence ....................................32
      12.11. Compromise of the PSK ...................................32
      12.12. Fragmentation ...........................................32
      12.13. Channel Binding .........................................32
      12.14. Fast Reconnect ..........................................33
      12.15. Identity Protection .....................................33
      12.16. Protected Ciphersuite Negotiation .......................33
      12.17. Confidentiality .........................................34
      12.18. Cryptographic Binding ...................................34
   13. IANA Considerations ...........................................34
   14. Contributors ..................................................35
   15. Acknowledgments ...............................................36