


Network Working Group                                         V. Cakulev
Internet-Draft                                            Alcatel Lucent
Intended status: Standards Track                                 A. Lior
Expires: May 17, 2012                                Bridgewater Systems
                                                           S. Mizikovsky
                                                          Alcatel Lucent
                                                       November 14, 2011


Diameter IKEv2 SK: Shared Key-based Support for IKEv2 Server to Diameter
                           Server Interaction
               draft-ietf-dime-ikev2-psk-diameter-11.txt

Abstract

   The Internet Key Exchange protocol version 2 (IKEv2) is a component
   of the IPsec architecture and is used to perform mutual
   authentication as well as to establish and to maintain IPsec security
   associations (SAs) between the respective parties.  IKEv2 supports
   several different authentication mechanisms, such as the Extensible
   Authentication Protocol (EAP), certificates, and shared key.

   Diameter interworking for Mobile IPv6 between the Home Agent, as a
   Diameter client, and the Diameter server has been specified.
   However, that specification focused on the usage of EAP and did not
   include support for shared key based authentication available with
   IKEv2.  This document specifies the IKEv2 Server to the Diameter
   server communication when the IKEv2 Peer authenticates using the
   Internet Key Exchange v2 with Shared Key.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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 May 17, 2012.

Copyright Notice



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   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
   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.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Requirements notation  . . . . . . . . . . . . . . . . . . . .  5
     2.1.  Abbreviations  . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Application Identifier . . . . . . . . . . . . . . . . . . . .  6
   4.  Protocol Description . . . . . . . . . . . . . . . . . . . . .  7
     4.1.  Support for IKEv2 and Shared Keys  . . . . . . . . . . . .  7
     4.2.  Session Management . . . . . . . . . . . . . . . . . . . .  8
       4.2.1.  Session-Termination-Request/Answer . . . . . . . . . .  8
       4.2.2.  Abort-Session-Request/Answer . . . . . . . . . . . . .  9
   5.  Command Codes for Diameter IKEv2 with SK . . . . . . . . . . . 10
     5.1.  IKEv2-SK-Request (IKESKR) Command  . . . . . . . . . . . . 10
     5.2.  IKEv2-SK-Answer (IKESKA) Command . . . . . . . . . . . . . 11
   6.  Attribute Value Pair Definitions . . . . . . . . . . . . . . . 13
     6.1.  IKEv2-Nonces . . . . . . . . . . . . . . . . . . . . . . . 13
       6.1.1.  Ni . . . . . . . . . . . . . . . . . . . . . . . . . . 13
       6.1.2.  Nr . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     6.2.  IKEv2-Identity . . . . . . . . . . . . . . . . . . . . . . 13
       6.2.1.  Initiator-Identity . . . . . . . . . . . . . . . . . . 13
       6.2.2.  Responder-Identity . . . . . . . . . . . . . . . . . . 14
   7.  AVP Occurrence Tables  . . . . . . . . . . . . . . . . . . . . 15
   8.  AVP Flag Rules . . . . . . . . . . . . . . . . . . . . . . . . 16
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 17
     9.1.  Command Codes  . . . . . . . . . . . . . . . . . . . . . . 17
     9.2.  AVP Codes  . . . . . . . . . . . . . . . . . . . . . . . . 17
     9.3.  AVP Values . . . . . . . . . . . . . . . . . . . . . . . . 17
     9.4.  Application Identifier . . . . . . . . . . . . . . . . . . 18
   10. Security Considerations  . . . . . . . . . . . . . . . . . . . 19
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 20
     11.2. Informative References . . . . . . . . . . . . . . . . . . 20
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22




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1.  Introduction

   The Internet Key Exchange version 2 (IKEv2) protocol [RFC5996] is
   used to mutually authenticate two parities and to establish a
   security association (SA) that can be used to efficiently secure the
   communication between the IKEv2 Peer and Server, for example, using
   Encapsulating Security Payload (ESP) [RFC4303] and/or Authentication
   Header (AH) [RFC4302].  The IKEv2 protocol allows several different
   mechanisms for authenticating a IKEv2 Peer to be used, such as the
   Extensible Authentication Protocol, certificates, and shared key.

   From a service provider perspective, it is important to ensure that a
   user is authorized to use the services.  Therefore, the IKEv2 Server
   must verify that the IKEv2 Peer is authorized for the requested
   services possibly with the assistance of the operator's Diameter
   servers.  [RFC5778] defines the home agent as a Diameter client to
   the Diameter server communication when the mobile node authenticates
   using the IKEv2 protocol with the Extensible Authentication Protocol
   (EAP) [RFC3748] or using the Mobile IPv6 Authentication Protocol
   [RFC4285].  This document specifies the IKEv2 Server to the Diameter
   server communication when the IKEv2 Peer authenticates using the
   Internet Key Exchange v2 with Shared Key.

   Figure 1 depicts the reference architecture for this document.



                                        +--------+
                                        |Diameter|
                                        |Server  |
                                        +--------+
                                            ^
                                   Back-End | IKEv2 Server<->HAAA Server
                                   Support  | Interaction
                                   Protocol | (this document)
                                            v
    +---------+                      +---------------+
    | IKEv2   |  Front-End Protocol  |IKEv2 Server/  |
    | Peer    |<-------------------->|Diameter Client|
    +---------+       IKEv2          +---------------+



                      Figure 1: Architecture Overview

   An example use case for this architecture is Mobile IPv6 deployment
   in which the Mobile IPv6 signaling between the Mobile Node and the
   Home Agent is protected using IPsec.  The Mobile node acts as the



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   IKEv2 Peer and the Home Agent acts as an IKEv2 server.  In this use
   case Internet Key Exchange v2 (IKEv2) with shared key based initiator
   authentication is used for the setup of the IPsec SAs.  The HA
   obtains the shared key using the Diameter application specified in
   this document.

   This document does not assume that the IKEv2 Server has the shared
   key (SK) with the IKEv2 Peer.  Instead it assumes that the SK
   provided to the IKEv2 Peer, as well as the SK delivered to the IKEv2
   Server by the Diameter Server, are established or derived using the
   same rules.  Furthermore, it assumes that these rules are agreed to
   by the external protocol on a Peer side providing the key to the
   IKEv2 Peer, and on the Diameter Server side providing the key to the
   IKEv2 Server.  This document allows for the SK to be obtained for a
   specific IKEv2 session and exchanged between IKEv2 Server and the
   Home Authentication, Authorization and Accounting (HAAA) server.  The
   protocol provides IKEv2 attributes to allow the HAAA to compute the
   SK specific for the session if desired (see Section 10).  This is
   accomplished through the use of a new Diameter application
   specifically designed for performing IKEv2 authorization decisions.
   This document focuses on the IKEv2 server, as a Diameter client,
   communicating to the Diameter server, and specifies the Diameter
   application needed for this communication.  Other protocols
   leveraging this Diameter application MAY specify their own SK
   derivation scheme For example see [X.S0047] and [X.S0058].  This
   document specifies the default procedure for derivation of the SK
   used in IKEv2 authentication when protocols leveraging this Diameter
   application do not specify their own derivation procedure.  Selection
   of either default or other SK derivation procedure is done by the
   external protocol between the Peer side providing the key to the
   IKEv2 Peer, and the Diameter Server, and is outside the scope of this
   document.



















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2.  Requirements notation

   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 [RFC2119].

2.1.  Abbreviations

   AH        Authentication Header

   AVP       Attribute Value Pair

   EAP       Extensible Authentication Protocol

   ESP       Encapsulating Security Payload

   ESP       Home Authentication, Authorization and Accounting

   IKEv2     Internet Key Exchange version 2

   NAI       Network Access Identifier

   PSK       Pre-Shared Key

   SA        Security Association

   SK        Shared Key

   SPI       Security Parameter Index






















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3.  Application Identifier

   This specification defines a new Diameter application and its
   respective Application Identifier:

      Diameter IKE SK  (IKESK)  TBD1 by IANA


   The IKESK Application Identifier is used when the IKEv2 Peer is to be
   authenticated and authorized using IKEv2 with SK-based
   authentication.








































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4.  Protocol Description

4.1.  Support for IKEv2 and Shared Keys

   When IKEv2 is used with SK-based initiator authentication, the
   Diameter commands IKEv2-SK-Request/Answer defined in this document
   are used between IKEv2 server and a Home AAA server (HAAA) to
   authorize the IKEv2 Peer for the services.  Upon receiving the
   IKE_AUTH message from the IKEv2 Peer, the IKEv2 Server uses the
   information received in IDi [RFC5996] to identify the IKEv2 Peer and
   the SPI if available to determine the correct SK for this IKEv2 Peer.
   If there is no SK found associated with this IKEv2 Peer, the IKEv2
   Server MUST send an Authorize-Only (Auth-Request-Type set to
   "Authorize-Only") Diameter IKEv2-SK-Request message to the HAAA to
   obtain the SK.  If the IDi payload extracted from the IKE_AUTH
   message contains an identity that is meaningful for the Diameter
   infrastructure, such as a Network Access Identifier (NAI), it SHALL
   be used by the IKEv2 Server to populate the User-Name AVP in the
   Diameter message.  Otherwise it is out of scope of this document how
   the IKEv2 server maps the value received in IDi payload to the User-
   Name AVP and whether the User-Name AVP is included or not in the
   IKEv2-SK-Request message.  The IKEv2 Server SHALL also include in the
   same Diameter message the IKEv2-Nonces AVP with the initiator and
   responder nonces (Ni and Nr) exchanged during initial IKEv2 exchange.
   Finally, the IKEv2 Server SHALL include in the IKEv2-SK-Request
   message the IKEv2-Identity AVP.  Initiator-Identity AVP SHALL be
   populated with the IDi field extracted from the IKE_AUTH message.  If
   IDr payload was included in the IKE_AUTH message received from the
   IKEv2 Peer, the IKEv2 Server SHALL also include Responder-Identity
   AVP populated with the received IDr.

   The IKEv2 Server sends the IKEv2-SK-Request message to the IKEv2
   Peer's HAAA.  The Diameter message is routed to the correct HAAA as
   per [RFC3588].

   Upon receiving Diameter IKEv2-SK-Request message from the IKEv2
   Server, the HAAA SHALL use the User-Name AVP (if present) and/or
   Initiator-Identity AVP to retrieve the associated keying material.
   When the default SK generation procedure specified in this document
   is used, the Peer side that provides the SK to the IKEv2 Peer, as
   well as the Diameter Server, SHALL use the same SK derivation which
   follows the methodology similar to that specified in Section 3.1 of
   [RFC5295], specifically:

   SK = KDF(PSK, key label | "\0" | Ni | Nr | IDi | length)


   Where:



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   o  KDF is the default key derivation function based on HMAC-SHA-256
      as specified in Section 3.1.2 of [RFC5295].

   o  Pre-Share Key (PSK) is the key available to the protocol
      leveraging this Diameter application, e.g., the long term shared
      secret, or the Extended Master Session Key (EMSK) as the result of
      prior EAP authentication etc.  Selection of this value is left up
      to the protocol leveraging this Diameter application.

   o  Key label is set to 'sk4ikev2@ietf.org'.

   o  | denotes concatenation

   o  "\0" is a NULL octet (0x00 in hex)

   o  Length is a 2-octet unsigned integer in network byte order of the
      output key length in octets.

   When applications using this protocol define their own SK generation
   algorithm it is strongly RECOMMENDED that the nonces Ni and Nr are
   used in the computation.  It is also RECOMMENDED that IDi be used.
   IDr SHOULD NOT be used in the SK generation algorithm.  Applications
   that want to use IDr in the computation should take into
   consideration that the IDr asserted by the IKEv2 peer may not be the
   same as the IDr returned by the IKEv2 responder.  This mismatch will
   result in different SKs being generated.  The HAAA returns the SK to
   the IKEv2 Server using the Key AVP as specified in
   [I-D.ietf-dime-local-keytran].

   Once the IKEv2 Server receives the SK from the HAAA, the IKEv2 Server
   verifies the IKE_AUTH message received from the IKEv2 Peer.  If the
   verification of AUTH is successful, the IKEv2 Server sends the IKE
   message back to the IKEv2 Peer.

4.2.  Session Management

   The HAAA may maintain Diameter session state or may be stateless.
   This is indicated by the presence or absence of the Auth-Session-
   State AVP included in the Answer message.  The IKEv2 Server MUST
   support the Authorization Session State Machine defined in [RFC3588].

4.2.1.  Session-Termination-Request/Answer

   In the case where HAAA is maintaining session state, when the IKEv2
   Server terminates the SA it SHALL send a Session-Termination-Request
   (STR) message [RFC3588] to inform the HAAA that the authorized
   session has been terminated.




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   The Session-Termination-Answer (STA) message [RFC3588] is sent by the
   HAAA to acknowledge the notification that the session has been
   terminated.

4.2.2.  Abort-Session-Request/Answer

   The Abort-Session-Request (ASR) message [RFC3588] is sent by the HAAA
   to the IKEv2 Server to terminate the authorized session.  When the
   IKEv2 Server receives the ASR message, it MUST delete the
   corresponding IKE_SA and all CHILD_SAs set up through it.

   The Abort-Session-Answer (ASA) message [RFC3588] is sent by the IKEv2
   Server in response to an ASR message.






































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5.  Command Codes for Diameter IKEv2 with SK

   This section defines new Command-Code values that MUST be supported
   by all Diameter implementations conforming to this specification.

     +------------------+---------+------+-------------+-------------+
     |   Command-Name   | Abbrev. | Code |  Reference  | Application |
     +------------------+---------+------+-------------+-------------+
     | IKEv2-SK-Request |  IKESKR | TBD2 | Section 5.1 |    IKESK    |
     |                  |         |      |             |             |
     |  IKEv2-SK-Answer |  IKESKA | TBD2 | Section 5.2 |    IKESK    |
     +------------------+---------+------+-------------+-------------+

                          Table 1: Command Codes

5.1.  IKEv2-SK-Request (IKESKR) Command

   The IKEv2-SK-Request message, indicated with the Command-Code set to
   TBD2 and the 'R' bit set in the Command Flags field, is sent from the
   IKEv2 Server to the HAAA to initiate IKEv2 with SK authorization.  In
   this case, the Application-ID field of the Diameter Header MUST be
   set to the Diameter IKE SK Application ID (value of TDB1).

   Message format


         <IKEv2-SK-Request> ::= < Diameter Header: TBD2, REQ, PXY >
                                 < Session-Id >
                                 { Auth-Application-Id }
                                 { Origin-Host }
                                 { Origin-Realm }
                                 { Destination-Realm }
                                 { Auth-Request-Type }
                                 [ Destination-Host ]
                                 [ NAS-Identifier ]
                                 [ NAS-IP-Address ]
                                 [ NAS-IPv6-Address ]
                                 [ NAS-Port ]
                                 [ Origin-State-Id ]
                                 [ User-Name ]
                                 [ Key-SPI ]
                                 { IKEv2-Identity }
                                 [ Auth-Session-State ]
                                 { IKEv2-Nonces }
                               * [ Proxy-Info ]
                               * [ Route-Record ]
                                 ...
                               * [ AVP ]



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   The IKEv2-SK-Request message MUST include a IKEv2-Nonces AVP
   containing the Ni and Nr nonces exchanged during initial IKEv2
   exchange.  The IKEv2-SK-Request message MAY contain a Key-SPI AVP
   (Key-SPI AVP is specified in [I-D.ietf-dime-local-keytran]).  If
   included, it contains the Security Parameter Index (SPI) that HAAA
   SHALL use, in addition to the other parameters (e.g., Initiator-
   Identity), to identify the appropriate SK.  The IKEv2-SK-Request
   message MUST include IKEv2-Identity AVP.  The Initiator-Identity AVP
   SHALL contain IDi as received in IKE_AUTH message.  Responder-
   Identity AVP SHALL be included in the IKEv2-SK-Request message, if
   IDr payload was included in the IKE_AUTH message received from the
   IKEv2 Peer.  If included, Responder-Identity AVP contains the
   received IDr.

5.2.  IKEv2-SK-Answer (IKESKA) Command

   The IKEv2-SK-Answer (IKESKA) message, indicated by the Command-Code
   field set to TBD2 and the 'R' bit cleared in the Command Flags field,
   is sent by the HAAA to the IKEv2 Server in response to the IKESKR
   command.  In this case, the Application-ID field of the Diameter
   Header MUST be set to the Diameter IKE SK Application ID (value of
   TDB1).

   Message format


           <IKEv2-SK-Answer> ::= < Diameter Header: TBD2, PXY >
                                  < Session-Id >
                                  { Auth-Application-Id }
                                  { Auth-Request-Type }
                                  { Result-Code }
                                  { Origin-Host }
                                  { Origin-Realm }
                                  [ User-Name ]
                                  [ Key ]
                                  [ Responder-Identity ]
                                  [ Auth-Session-State ]
                                  [ Error-Message ]
                                  [ Error-Reporting-Host ]
                                * [ Failed-AVP ]
                                  [ Origin-State-Id ]
                                * [ Redirect-Host ]
                                  [ Redirect-Host-Usage ]
                                  [ Redirect-Max-Cache-Time ]
                                * [ Proxy-Info ]
                                * [ Route-Record ]
                                  ...
                                * [ AVP ]



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   If the authorization procedure is successful then the IKEv2-SK-Answer
   message SHALL include the Key AVP as specified in
   [I-D.ietf-dime-local-keytran].  The value of the Key-Type AVP SHALL
   be set to IKEv2-SK (TBD3).  The Keying-Material AVP SHALL contain the
   SK.  If Key-SPI AVP is received in IKEv2-SK-Request, Key-SPI AVP
   SHALL be included in Key AVP.  The Key-Lifetime AVP may be included
   and if it is included then the associated key SHALL NOT be used by
   the receiver of the answer if the lifetime has expired.  Finally,
   Responder-Identity AVP may be included.










































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6.  Attribute Value Pair Definitions

   This section defines new AVPs for the IKEv2 with SK.

6.1.  IKEv2-Nonces

   The IKEv2-Nonces AVP (Code TBD4) is of type Grouped and contains the
   nonces exchanged between the IKEv2 Peer and the IKEv2 Server during
   IKEv2 initial exchange.  The nonces are used for SK generation.


               IKEv2-Nonces ::= < AVP Header: TBD4>
                                {Ni}
                                {Nr}
                               *[AVP]

6.1.1.  Ni

   The Ni AVP (AVP Code TBD5) is of type OctetString and contains the
   IKEv2 initiator nonce as contained in Nonce Data field.

6.1.2.  Nr

   The Nr AVP (AVP Code TBD6) is of type OctetString and contains the
   IKEv2 responder nonce as contained in Nonce Data field.

6.2.  IKEv2-Identity

   The IKEv2-Identity AVP (Code TBD7) is of type Grouped and contains
   the Initiator and possibly Responder identities as included in
   IKE_AUTH message sent from the IKEv2 Peer to the IKEv2 Server.


               IKEv2-Identity ::= < AVP Header: TBD7>
                                {Initiator-Identity}
                                [Responder-Identity]
                               *[AVP]

6.2.1.  Initiator-Identity

   The Initiator-Identity AVP (AVP Code TBD8) is of type Grouped and
   contains the identity type and identification data of the IDi payload
   of the IKE_AUTH message.


               Initiator-Identity ::= < AVP Header: TBD8>
                                {ID-Type}
                                {Identification-Data}



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                               *[AVP]

6.2.1.1.  ID-Type

   The ID-Type AVP (AVP Code TBD9) is of type Enumerated and contains
   the ID type value of IDi payload of the IKE_AUTH message.

6.2.1.2.  Identification-Data

   The Identification-Data AVP (AVP Code TBD10) is of type OctetString
   and contains the Identification Data field of IDi payload of the
   IKE_AUTH message.

6.2.2.  Responder-Identity

   The Responder-Identity AVP (AVP Code TBD11) is of type Grouped and
   contains the identity type and identification data of the IDr payload
   of the IKE_AUTH message.


               Responder-Identity ::= < AVP Header: TBD8>
                                {ID-Type}
                                {Identification-Data}
                               *[AVP]

6.2.2.1.  ID-Type

   The ID-Type AVP (AVP Code TBD9) is of type Enumerated and contains
   the ID type value of IDr payload of the IKE_AUTH message.

6.2.2.2.  Identification-Data

   The Identification-Data AVP (AVP Code TBD10) is of type OctetString
   and contains the Identification Data field of IDr payload of the
   IKE_AUTH message.
















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7.  AVP Occurrence Tables

   The following tables present the AVPs defined or used in this
   document and their occurrences in Diameter messages.  Note that AVPs
   that can only be present within a Grouped AVP are not represented in
   this table.

   The table uses the following symbols:

   0:

      The AVP MUST NOT be present in the message.


   0+:

      Zero or more instances of the AVP MAY be present in the message.


   0-1:

      Zero or one instance of the AVP MAY be present in the message.


   1:

      One instance of the AVP MUST be present in the message.



                                     +-------------------+
                                     |   Command-Code    |
                                     |---------+---------+
      AVP Name                       | IKESKR  | IKESKA  |
      -------------------------------|---------+---------+
      Key                            |    0    |   0-1   |
      Key-SPI                        |   0-1   |    0    |
      IKEv2-Nonces                   |    1    |    0    |
      IKEv2-Identity                 |    1    |    0    |
      Responder-Identity             |    0    |   0-1   |
                                     +---------+---------+

                   IKESKR and IKESKA Commands AVP Table








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8.  AVP Flag Rules

   The following table describes the Diameter AVPs, their AVP Code
   values, types, and possible flag values.  The Diameter base [RFC3588]
   specifies the AVP Flag rules for AVPs in Section 4.5.


                                                 +--------------------+
                                                 |   AVP Flag rules   |
                                                 +----+---+------+----+
                       AVP  Defined              |    |   |SHOULD|MUST|
    Attribute Name      Code in       Value Type |MUST|MAY| NOT  | NOT|
   +---------------------------------------------+----+---+------+----+
   |Key                 TBD  Note 1   Grouped    |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Keying-Material     TBD  Note 1   OctetString|  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Key-Lifetime        TBD  Note 1   Integer64  |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Key-SPI             TBD  Note 1   Unsigned32 |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Key-Type            TBD  Note 1   Enumerated |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |IKEv2-Nonces        TBD4 6.1      Grouped    |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Ni                  TBD5 6.1.1    OctetString|  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Nr                  TBD6 6.1.2    OctetString|  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |IKEv2-Identity      TBD7 6.2      Grouped    |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Initiator-Identity  TBD8 6.2.1    Grouped    |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |ID-Type             TBD9 6.2.1.1  Enumerated |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Identification-Data TBD10 6.2.1.2 OctetString|  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+
   |Responder-Identity  TBD11 6.2.2   Grouped    |  M | P |      | V  |
   +---------------------------------------------+----+---+------+----+


                           AVP Flag Rules Table

   Note 1: Key, Keying-Material, Key-Type, Key-SPI and Key-Lifetime AVPs
   are defined in [I-D.ietf-dime-local-keytran].






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9.  IANA Considerations

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

9.1.  Command Codes

   IANA is requested to allocate a command code value for the following
   new command from the Command Code namespace defined in [RFC3588].

      Command Code                     | Value
      ---------------------------------+------
      IKEv2-SK-Request/Answer          | TBD2



9.2.  AVP Codes

   This specification requires IANA to register the following new AVPs
   from the AVP Code namespace defined in [RFC3588].


   o  IKEv2-Nonces - TBD4

   o  Ni - TBD5

   o  Nr - TBD6

   o  IKEv2-Identity - TBD7

   o  Initiator-Identity - TBD8

   o  ID-Type - TBD9

   o  Identification-Data - TBD10

   o  Responder-Identity - TBD11


   The AVPs are defined in Section 6.

9.3.  AVP Values

   IANA is requested to create a new value for the Key-Type AVP.  The
   new value TBD3 signifies that IKEv2 SK is being sent.






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9.4.  Application Identifier

   This specification requires IANA to allocate one new value "Diameter
   IKE SK" from the Application Identifier namespace defined in
   [RFC3588].

   Application Identifier         | Value
   -------------------------------+------
   Diameter IKE SK (IKESK)        | TBD1










































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10.  Security Considerations

   The security considerations of the Diameter Base protocol [RFC3588]
   are applicable to this document (e.g., it is expected that Diameter
   protocol is used with security mechanism and that Diameter messages
   are secured).

   In addition, the assumption is that the IKEv2 Server and the Diameter
   Server where the SK is generated are in a trusted relationship.
   Hence, the assumption is that there is an appropriate security
   mechanism to protect the communication between these servers.  For
   example the IKEv2 Server and the Diameter server would be deployed in
   the same secure network or would utilize transport layer security as
   specified in [RFC3588].

   The Diameter messages between the IKEv2 Server and the HAAA may be
   transported via one or more AAA brokers or Diameter agents.  In this
   case, the IKEv2 Server to the Diameter server AAA communication is
   hop-by-hop protected, hence relies on the security properties of the
   intermediating AAA inter- connection networks, AAA brokers, and
   Diameter agents.  Furthermore, any agents that process IKEv2-SK-
   Answer messages can see the contents of the Key AVP.

   To mitigate the threat of exposing long lived PSK, this specification
   expects that the HAAA derives and returns the associated SK to the
   IKEv2 Server.  Given that SK derivation is security-critical, for the
   SK derivation this specification recommends the use of short lived
   secrets, possibly based on a previous network access authentication,
   if such secrets are available.  To ensure key freshness and to limit
   the key scope, this specification strongly recommends the use of
   nonces included in IKEv2-SK-Request.  The specifics of key derivation
   depend on the security characteristics of the system that is
   leveraging this specification (for example see [X.S0047] and
   [X.S0058]), therefore this specification does not define how the
   Diameter server derives required keys for these systems.  For systems
   and protocols that leverage this Diameter application but do not
   specify the key derivation procedure, this document specifies the
   default key derivation procedure that preserves expected security
   characteristics.












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11.  References

11.1.  Normative References

   [I-D.ietf-dime-local-keytran]
              Zorn, G., Wu, W., and V. Cakulev, "Diameter Attribute-
              Value Pairs for Cryptographic Key Transport",
              draft-ietf-dime-local-keytran-10 (work in progress),
              May 2011.

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

   [RFC4302]  Kent, S., "IP Authentication Header", RFC 4302,
              December 2005.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, December 2005.

   [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.

   [RFC5996]  Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
              "Internet Key Exchange Protocol Version 2 (IKEv2)",
              RFC 5996, September 2010.

11.2.  Informative References

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

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

   [RFC4285]  Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
              Chowdhury, "Authentication Protocol for Mobile IPv6",
              RFC 4285, January 2006.

   [RFC5778]  Korhonen, J., Tschofenig, H., Bournelle, J., Giaretta, G.,
              and M. Nakhjiri, "Diameter Mobile IPv6: Support for Home
              Agent to Diameter Server Interaction", RFC 5778,
              February 2010.

   [X.S0047]  3GPP2: X.S0047, "Mobile IPv6 Enhancements", February 2009.




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   [X.S0058]  3GPP2: X.S0058, "WiMAX-HRPD Interworking: Core Network
              Aspects", June 2010.

















































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Authors' Addresses

   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


   Avi Lior
   Bridgewater Systems
   303 Terry Fox Drive
   Ottawa, Ontario  K2K 3J1
   Canada

   Phone: +1 613-591-6655
   Email: avi@bridgewatersystems.com


   Semyon Mizikovsky
   Alcatel Lucent
   600 Mountain Ave.
   3C-506
   Murray Hill, NJ  07974
   US

   Phone: +1 908 582 0729
   Email: Simon.Mizikovsky@alcatel-lucent.com



















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