Network Working Group                                         Q. Wu, Ed.
Internet-Draft                             Huawei Technologies Co., Ltd.
Updates: 4072 (if approved)                                 G. Zorn, Ed.
Intended status: Standards Track                             Network Zen
Expires: January 8, 2010                                    July 7, 2009


     Diameter Attribute-Value Pairs for Cryptographic Key Transport
                     draft-wu-dime-local-keytran-02

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Abstract

   Some AAA applications require the transport of cryptographic keying
   material; this document specifies a set of Attribute-Value Pairs



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   (AVPs) providing native Diameter support of cryptographic key
   delivery.


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.  EAP-Key AVP . . . . . . . . . . . . . . . . . . . . . . . . 4
       3.1.1.  EAP-Key-Type AVP  . . . . . . . . . . . . . . . . . . . 5
       3.1.2.  EAP-Key-Name AVP  . . . . . . . . . . . . . . . . . . . 5
       3.1.3.  EAP-Keying-Material AVP . . . . . . . . . . . . . . . . 5
       3.1.4.  EAP-Key-Lifetime AVP  . . . . . . . . . . . . . . . . . 6
   4.  AVP Occurrence Table  . . . . . . . . . . . . . . . . . . . . . 6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
     6.1.  AVP Codes . . . . . . . . . . . . . . . . . . . . . . . . . 6
     6.2.  AVP Values  . . . . . . . . . . . . . . . . . . . . . . . . 7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8


























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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
   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 [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, 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

   The following terms are used in this note.

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

   AAA
      Authentication, Authorization, and Accounting (see below).

   Accounting
      The act of collecting information on resource usage for the
      purpose of trend analysis, auditing, billing, or cost allocation
      [RFC2989].

   Authentication
      The act of verifying a claimed identity, in the form of a pre-
      existing label from a mutually known name space, as the originator
      of a message (message authentication) or as the end-point of a
      channel (entity authentication) [RFC2989].

   Authorization
      The act of determining if a particular right, such as access to
      some resource, can be granted to the presenter of a particular
      credential [RFC2989].



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   DER
      Diameter EAP request.  [RFC4072]

   DEA
      Diameter EAP Answer.  [RFC4072]

   DSRK
      Domain Specific Root Key [RFC5295].

   EAP
      Extensible Authentication Protocol [RFC3748].

   EMSK
      Extended Master Session Key [RFC3748].

   ERP
      EAP Re-authentication Protocol [RFC5296].

   MSK
      Master Session Key [RFC3748].

   rMSK
      re-authentication MSK [RFC5296].  This is a per-authenticator key,
      derived from the rRK.

   rRK
      re-authentication Root Key, derived from the EMSK or DSRK
      [RFC5296].

   USRK
      Usage Specific Root Key [RFC5295].


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.  EAP-Key AVP

   The EAP-Key AVP (AVP Code <AC1>) is of type Grouped [RFC3588].  It
   contains the name, type and optionally, the usable lifetime of the
   key, as well as the keying material itself.







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

3.1.1.  EAP-Key-Type AVP

   The EAP-Key-Type AVP (AVP Code <AC2>) is of type Enumerated and
   signifies the type of the key being sent.  The EAP-Key-Type MAY be
   included in a DER command as a signal that a certain type of key is
   required in the response (e.g., to support ERP).  The following
   values are defined in this document:

   MSK (0)
      The EAP Master Session Key [RFC3748].

   DSRK (1)
      A Domain Specific Root Key [RFC5295].

   USRK (2)
      A Usage Specific Root Key [RFC5295].

   rRK (3)
      A reauthentication Root Key [RFC5296].

   rMSK (4)
      A reauthentication Master Session Key [RFC5296].

   DSUSRK (5)
      A Domain Specific Usage Specific Root Key [RFC5295].

   If additional values are needed, they are to be assigned by IANA
   according to the policy stated in Section 6.2.

3.1.2.  EAP-Key-Name AVP

   The syntax and semantics of the EAP-Key-Name AVP are specified in
   Section 4.1.4 of RFC 4072.

3.1.3.  EAP-Keying-Material AVP

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




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3.1.4.  EAP-Key-Lifetime AVP

   The EAP-Key-Lifetime AVP (AVP Code <AC4>) is of type Integer64
   [RFC3588] representing the period of time (in seconds) for which the
   keying material is valid.

   Note: Applications using this value SHOULD consider the beginning of
   the lifetime to be the point in time when the keying material is
   first used.


4.  AVP Occurrence Table

   The following table lists the AVPs that MAY be present in the DER and
   DEA commands [RFC4072].

                                            +---------------+
                                            |  Command-Code |
                                            +-+-----+-----+-+
               AVP Name                       | DER | DEA |
               -------------------------------|-----+-----+
               EAP-Key                        |  0  |  0+ |
               EAP-Key-Type                   |  0+ |  0  |
               EAP-Key-Name                   | 0-1 | 0-1 |
                                              +-----+-----+

                        DER and DEA Commands AVP Table


5.  Security Considerations

   The security considerations discussed in [RFC3588] are applicable to
   this document.


6.  IANA Considerations

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

6.1.  AVP Codes

   Codes must be assigned for the following AVPs using the policy
   specified in RFC 3588, Section 11.1.1:

   o  EAP-Key (<AC1>, Section 3.1)





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

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

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

6.2.  AVP Values

   New values may be assigned for the EAP-Key-Type AVP (Section 3.1.1)
   using the "First Come, First Served" policy [RFC5226].


7.  References

7.1.  Normative References

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

   [RFC3588]  Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
              Arkko, "Diameter Base Protocol", RFC 3588, September 2003.

   [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

   [RFC2989]  Aboba, B., Calhoun, P., Glass, S., Hiller, T., McCann, P.,
              Shiino, H., Zorn, G., Dommety, G., C.Perkins, B.Patil,
              D.Mitton, S.Manning, M.Beadles, P.Walsh, X.Chen,
              S.Sivalingham, A.Hameed, M.Munson, S.Jacobs, B.Lim,
              B.Hirschman, R.Hsu, Y.Xu, E.Campell, S.Baba, and E.Jaques,
              "Criteria for Evaluating AAA Protocols for Network
              Access", RFC 2989, November 2000.

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

   [RFC5295]  Salowey, J., Dondeti, L., Narayanan, V., and M. Nakhjiri,



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              "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

   Qin Wu (editor)
   Huawei Technologies Co., Ltd.
   Site B, Floor 12F, Huihong Mansion, No.91 Baixia Rd.
   Nanjing, Jiangsu  21001
   China

   Phone: +86-25-84565892
   Email: sunseawq@huawei.com


   Glen Zorn (editor)
   Network Zen
   1310 East Thomas Street
   #306
   Seattle, Washington  98102
   USA

   Phone: +1 (206) 377-9035
   Email: gwz@net-zen.net






















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