


Network Working Group                                            G. Zorn
Internet-Draft                                               Network Zen
Intended status: Standards Track                                   Q. Wu
Expires: February 20, 2012                                        Huawei
                                                              V. Cakulev
                                                          Alcatel Lucent
                                                         August 19, 2011


     Diameter Attribute-Value Pairs for Cryptographic Key Transport
                    draft-ietf-dime-local-keytran-14

Abstract

   Some Authentication, Authorization, and Accounting (AAA) applications
   require the transport of cryptographic keying material.  This
   document specifies a set of Attribute-Value Pairs (AVPs) providing
   native Diameter support of cryptographic key delivery.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 20, 2012.

Copyright Notice

   Copyright (c) 2011 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
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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of



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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     2.1.  Standards Language  . . . . . . . . . . . . . . . . . . . . 3
     2.2.  Technical Terms and Acronyms  . . . . . . . . . . . . . . . 3
   3.  Attribute-Value Pair Definitions  . . . . . . . . . . . . . . . 4
     3.1.  Key AVP . . . . . . . . . . . . . . . . . . . . . . . . . . 4
       3.1.1.  Key-Type AVP  . . . . . . . . . . . . . . . . . . . . . 4
       3.1.2.  Key-Name AVP  . . . . . . . . . . . . . . . . . . . . . 4
       3.1.3.  Keying-Material AVP . . . . . . . . . . . . . . . . . . 5
       3.1.4.  Key-Lifetime AVP  . . . . . . . . . . . . . . . . . . . 5
       3.1.5.  Key-SPI . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
     5.1.  AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . . 6
     5.2.  AVP Values  . . . . . . . . . . . . . . . . . . . . . . . . 6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 6
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7

























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1.  Introduction

   The Diameter EAP application [RFC4072] defines the EAP-Master-
   Session-Key and EAP-Key-Name AVPs for the purpose of transporting
   cryptographic keying material derived during the execution of certain
   Extensible Authentication Protocol (EAP) [RFC3748] methods (for
   example, EAP-TLS [RFC5216]).  At most one instance of either of these
   AVPs is allowed in any Diameter message.

   However, recent work (see, for example, [RFC5295]) has specified
   methods to derive other keys from the keying material created during
   EAP method execution that may require transport in addition to the
   MSK.  In addition, the EAP Re-authentication Protocol (ERP) [RFC5296]
   specifies new keys that may need to be transported between Diameter
   nodes.

   This note specifies a set of AVPs allowing the transport of multiple
   cryptographic keys in a single Diameter message.


2.  Terminology

2.1.  Standards Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.2.  Technical Terms and Acronyms

   DSRK
      Domain-Specific Root Key [RFC5295].

   MSK
      Master Session Key [RFC3748].

   rMSK
      reauthentication MSK [RFC5296].  This is a per-authenticator key,
      derived from the rRK (below).

   rRK
      reauthentication Root Key, derived from the EMSK Extended Master
      Session Key [RFC3748] or DSRK [RFC5296].








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3.  Attribute-Value Pair Definitions

   This section defines new AVPs for the transport of cryptographic keys
   in the Diameter EAP application [RFC4072], as well as other Diameter
   applications.

3.1.  Key AVP

   The Key AVP (AVP Code <AC1>) is of type Grouped.  It contains the
   type and keying material and, optionally, an indication of the usable
   lifetime of the key, the name of the key and a Security Parameter
   Index (SPI) with which the key is associated.

   Key ::= < AVP Header: AC1 >
             < Key-Type >
             { Keying-Material }
             [ Key-Lifetime ]
             [ Key-Name ]
             [ Key-SPI ]
           * [ AVP ]

3.1.1.  Key-Type AVP

   The Key-Type AVP (AVP Code <AC2>) is of type Enumerated.  This AVP
   identifies the type of the key being sent.  The following decimal
   values are defined in this document:

   DSRK (0)
      A Domain-Specific Root Key [RFC5295].

   rRK (1)
      A reauthentication Root Key [RFC5296].

   rMSK (2)
      A reauthentication Master Session Key [RFC5296].

   If additional values are needed, they are to be assigned by IANA
   according to the policy stated in Section 5.2,

3.1.2.  Key-Name AVP

   The Key-Name AVP (AVP Code <AC6>) is of type OctetString.  It
   contains an opaque key identifier.  Exactly how this name is
   generated and used depends on the key type and usage in question, and
   is beyond the scope of this document (see [RFC5247] and [RFC5295] for
   discussions of key name generation in the context of EAP).





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3.1.3.  Keying-Material AVP

   The Keying-Material AVP (AVP Code <AC3>) is of type OctetString.  The
   exact usage of this keying material depends upon several factors,
   including the type of the key and the link layer in use and is beyond
   the scope of this document.

3.1.4.  Key-Lifetime AVP

   The Key-Lifetime AVP (AVP Code <AC4>) is of type Unsigned32 and
   represents the period of time (in seconds) for which the contents of
   the Keying-Material AVP (Section 3.1.3) is valid.

   NOTE:
      Applications using this value SHOULD consider the beginning of the
      lifetime to be the point in time when the message containing the
      keying material is received.  In addition, client implementations
      SHOULD check to ensure that the value is reasonable; for example,
      the lifetime of a key should not generally be longer than the
      session lifetime (see section 8.13 of [I-D.ietf-dime-rfc3588bis].

3.1.5.  Key-SPI

   The Key-SPI AVP (AVP Code <AC5>) is of type Unsigned32 and contains a
   SPI value that can be used with other parameters for identifying
   associated keying material.


4.  Security Considerations

   Transporting keys is a security-sensitive action.  Some forms of
   keying material are already protected and can be sent safely over the
   open Internet.  However, if a Key AVP contains Keying-Material that
   is not already protected, then the Diameter messages containing that
   Key AVP MUST only be sent protected via mutually authenticated TLS or
   IPsec.

   The security considerations applicable to the Diameter Base Protocol
   [I-D.ietf-dime-rfc3588bis] are also applicable to this document, as
   are those in Section 8.4 of RFC 4072 [RFC4072].


5.  IANA Considerations

   Upon publication of this memo as an RFC, IANA is requested to assign
   values as described in the following sections.





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5.1.  AVP Codes

   Codes must be assigned for the following AVPs using the policy
   specified in [I-D.ietf-dime-rfc3588bis], Section 11.1.1:

   o  Key (<AC1>, Section 3.1)

   o  Key-Type (<AC2>, Section 3.1.1)

   o  Keying-Material (<AC3>, Section 3.1.3)

   o  Key-Lifetime (<AC4>, Section 3.1.4)

   o  Key-SPI (<AC5>, Section 3.1.5)

   o  Key-Name (<AC6>, Section 3.1.2)

5.2.  AVP Values

   IANA is requested to create a new registry for values assigned to the
   Key-Type AVP and populated with the decimal values defined in this
   document (Section 3.1.1).  New values may be assigned for the Key-
   Type AVP using the "Specification Required" policy [RFC5226]; once
   values have been assigned, they MUST NOT be deleted, replaced or
   modified.


6.  Acknowledgements

   Thanks (in no particular order) to Niclas Comstedt, Semyon
   Mizikovsky, Hannes Tschofenig, Joe Salowey, Tom Taylor, Frank Xia,
   Lionel Morand, Dan Romascanu, Bernard Aboba, Jouni Korhonen, Stephen
   Farrel, Joel Halpern, Phillip Hallam-Baker, Sean Turner and Sebastien
   Decugis for useful comments, suggestions and review.


7.  References

7.1.  Normative References

   [I-D.ietf-dime-rfc3588bis]
              Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
              "Diameter Base Protocol", draft-ietf-dime-rfc3588bis-26
              (work in progress), January 2011.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.




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   [RFC3748]  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
              Levkowetz, "Extensible Authentication Protocol (EAP)",
              RFC 3748, June 2004.

   [RFC4072]  Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
              Authentication Protocol (EAP) Application", RFC 4072,
              August 2005.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

7.2.  Informative References

   [RFC5216]  Simon, D., Aboba, B., and R. Hurst, "The EAP-TLS
              Authentication Protocol", RFC 5216, March 2008.

   [RFC5247]  Aboba, B., Simon, D., and P. Eronen, "Extensible
              Authentication Protocol (EAP) Key Management Framework",
              RFC 5247, August 2008.

   [RFC5295]  Salowey, J., Dondeti, L., Narayanan, V., and M. Nakhjiri,
              "Specification for the Derivation of Root Keys from an
              Extended Master Session Key (EMSK)", RFC 5295,
              August 2008.

   [RFC5296]  Narayanan, V. and L. Dondeti, "EAP Extensions for EAP Re-
              authentication Protocol (ERP)", RFC 5296, August 2008.


Authors' Addresses

   Glen Zorn
   Network Zen
   227/358 Thanon Sanphawut
   Bang Na, Bangkok  10260
   Thailand

   Phone: +66 (0) 87-040-4617
   Email: glenzorn@gmail.com











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   Qin Wu
   Huawei Technologies Co., Ltd.
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  21001
   China

   Phone: +86-25-56623633
   Email: sunseawq@huawei.com


   Violeta Cakulev
   Alcatel Lucent
   600 Mountain Ave.
   3D-517
   Murray Hill, NJ  07974
   US

   Phone: +1 908 582 3207
   Email: violeta.cakulev@alcatel-lucent.com
































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