IBAKE: Identity-Based Authenticated Key Exchange
RFC 6539

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Independent Submission                                        V. Cakulev
Request for Comments: 6539                                   G. Sundaram
Category: Informational                                      I. Broustis
ISSN: 2070-1721                                           Alcatel Lucent
                                                              March 2012

            IBAKE: Identity-Based Authenticated Key Exchange

Abstract

   Cryptographic protocols based on public-key methods have been
   traditionally based on certificates and Public Key Infrastructure
   (PKI) to support certificate management.  The emerging field of
   Identity-Based Encryption (IBE) protocols allows simplification of
   infrastructure requirements via a Private-Key Generator (PKG) while
   providing the same flexibility.  However, one significant limitation
   of IBE methods is that the PKG can end up being a de facto key escrow
   server, with undesirable consequences.  Another observed deficiency
   is a lack of mutual authentication of communicating parties.  This
   document specifies the Identity-Based Authenticated Key Exchange
   (IBAKE) protocol.  IBAKE does not suffer from the key escrow problem
   and in addition provides mutual authentication as well as perfect
   forward and backward secrecy.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see 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/rfc6539.

Independent Submissions Editor Note

   This document specifies the Identity-Based Authenticated Key Exchange
   (IBAKE) protocol.  Due to its specialized nature, this document
   experienced limited review within the Internet Community.  Readers of
   this RFC should carefully evaluate its value for implementation and
   deployment.

Cakulev, et al.               Informational                     [Page 1]
RFC 6539                          IBAKE                       March 2012

Copyright Notice

   Copyright (c) 2012 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Table of Contents

   1. Introduction ....................................................2
   2. Requirements Notation ...........................................3
      2.1. IBE: Definition ............................................3
      2.2. Abbreviations ..............................................3
      2.3. Conventions ................................................4
   3. Identity-Based Authenticated Key Exchange .......................5
      3.1. Overview ...................................................5
      3.2. IBAKE Message Exchange .....................................6
      3.3. Discussion .................................................7
   4. Security Considerations .........................................9
      4.1. General ....................................................9
      4.2. IBAKE Protocol ............................................10
   5. References .....................................................12
      5.1. Normative References ......................................12
      5.2. Informative References ....................................12

1.  Introduction

   Authenticated key agreements are cryptographic protocols where two or
   more participants authenticate each other and agree on key material
   used for securing future communication.  These protocols could be
   symmetric key or asymmetric public-key protocols.  Symmetric-key
   protocols require an out-of-band security mechanism to bootstrap a
   secret key.  On the other hand, public-key protocols traditionally
   require certificates and a large-scale Public Key Infrastructure
   (PKI).  Clearly, public-key methods are more flexible; however, the
   requirement for certificates and a large-scale PKI have proved to be
   challenging.  In particular, efficient methods to support large-scale
   certificate revocation and management have proved to be elusive.

   Recently, Identity-Based Encryption (IBE) protocols have been
   proposed as a viable alternative to public-key methods by replacing
   the PKI with a Private-Key Generator (PKG).  However, one significant