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Federated Cross-Layer Access
draft-wei-abfab-fcla-01

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This is an older version of an Internet-Draft whose latest revision state is "Expired".
Author Yinxing Wei
Last updated 2011-10-31 (Latest revision 2011-07-04)
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draft-wei-abfab-fcla-01
ABFAB                                                        Y. Wei, Ed.
Internet-Draft                                           ZTE Corporation
Intended status: Informational                          October 31, 2011
Expires: May 3, 2012

                      Federated Cross-Layer Access
                        draft-wei-abfab-fcla-01

Abstract

   Network stratum and application stratum form a federation to
   faciliate user's access.  Network operator acts as Identity Provider
   (IdP), and application reuses underlying network's security
   capabilities to simlify application's access.  This document is to
   introduce such federated cross-layer access use case and message
   flows.

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
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   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 May 3, 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
   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
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Related Work  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Use Case  . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   4.  Message Flow  . . . . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 8
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 9

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1.  Introduction

   Currently it is agreed that digital identity is a crucial element in
   a service enviroment.  Typically telecom operators provide access
   customers with identity which is associated with some form of trusted
   element on the network (e.g.  SIM/UICC).  Meanwhile the identity
   required by Web or non-Web services for users on is usually
   associated with username.

   Ordinarly telecom operators have tens of millons of users and can
   provide trusted identity and higher security.  However the categories
   of service provided by telecom operators are relatively few.  On the
   contrary most service providers on the Internet have limited amount
   of users and can not assure the security of user identity, but they
   can provide abundant kinds of service.  Furthermore, user is
   reluntant to register too many accounts because it is inconvenient to
   remember dozens of passwords .  These facts creates some driving
   forces that telecom is interworking with Internet.  The stakeholders
   can benifit from these combination.  For telecom operators, they can
   provide identity service, trusted security service, mobile payment
   service and sharing some user profiles according user's preferences.
   Telecom operators is not just providing pipeine for communication,
   but also become a part of service value chain.  For service
   providers, they can focus on core business and reuse capabilities
   provided by telecom operators without worring about sources of users.
   For end users, they can enjoy seamless service experiences and
   improve security and privacy.

   This document considers a use case which telecom operator acts as
   Identity provider (IdP) and federates with non-Web applications, e.g.
   Email, Messaging.  This use case combines network stratum access and
   application stratum access, which is named as federated cross-layer
   access.  The detailed message flows for this use case are given.

2.  Related Work

   GSMA Association IDM project address operators' requirements for
   emerging mobile application (such as, Single Sign-on, mobile payments
   and other UICC enabled applications).  Several use cases are also
   identified[GSMA_IDM].  Liberty Alliance Telecommunications SIG
   investigates digital identity grown in both telecom and Internet,
   develops several use cases and proposes correspoding solutions for
   interworking these two different domains [TelecoSiG].

   GBA (Generic Bootsrapping Authentication) mechanism for boostrapping
   authentication and key agreement for application is denfined in
   [TS33.220].  The interworking between GBA and Identity Federation

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   Framework (ID-FE) is documented in [TR33.980].  Another interworking
   case between GBA and OpenID is specified in [TR33.924].

   Currently some use cases [I-D.ietf-abfab-usecases], architecture
   [I-D.lear-abfab-arch] and mechanisms are developed in IETF abfab
   working group.

3.  Use Case

   Editor's Note: The section WILL be removed if this use case is
   adopted in [I-D.ietf-abfab-usecases].

   Telecom operators have a communication network infrastructures to
   provider users with a wealthy of access methods.  Telecom operators
   have a huge number of registered users, and they can provide trusted
   identity and higher security.  Therefore they have a natural
   advantage to act as an Identity Provider (IdP) to serve for service
   providers.  On the contrary most service providers on the Internet
   have limited amount of users and can not assure the security of user
   identity, but they can provide abundant kinds of service.
   Furthermore, user is reluctant to register too many accounts because
   it is inconvenient to remember dozens of passwords.

   Telecom network supports Web or non-Web application.  In some cases
   user prefers to choose non-Web application, e.g.  Messaging service,
   VoIP, EMail service, etc.  Based on the result of network stratum
   authentication and authorization, User equipment (UE) can access
   applications without doing another authentication and authorization
   procedure.  In this way, the system can implement federated cross-
   layer access.  Firstly mutual authentication is performed between UE
   and Network, secondly UE accesses Application based on the result of
   network stratum's authentication.  In this case, a federation is
   formed between Network and Application.

   For federated cross-layer access, Network can assure the Application
   of the authenticity of user's identity, share some of use profile
   with Application.  These can bring some benifits to stakeholders:

   o  For telecom operators, it becomes part of the business value chain
      as an Identity Provider.
   o  For service provider, it can focus on core competitive services
      without worrying about the number of registered users by reusing
      underlying security mechanisms during network stratum access.
   o  For end users, seamless sevice is provided, security and privacy
      are improved.

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4.  Message Flow

   Take mobile network for example, UE has pre-shared key (PSK) with
   HSS.  UE is mutully authenticated with network during attach
   procedure.  After authentication, a master session key (MSK) is
   created on both UE and AAA.  EAP [RFC3748] can enable the above
   procedure.

                                          +-------------+
                                          + Application |
                                        / +------+------+
                                      /          |
                                    /            |
                                  /              |
                                /                |
                              /            +-----+----+
                         +---+--+          |          |
                         |  UE  +----------+  Network |
                         +------+          |          |
                                           +----------+

                  Figure 1: Federated Cross-Layer Access

   Figure 1 shows the relation among UE, network and application.
   Firstly mutual authentication is performed between UE and Network,
   secondly UE accesses Application using Single Sign-ON (SSO) based on
   network stratum's authentication.  In this case, a federation is
   formed between Network and Application.  The brief steps are as
   follows:

   1.  When UE attach the Network, mutual authentication is performed
       master session key is created between them.
   2.  UE visits non-Web Application, e.g Messageing service, VoIP
       service, or Email service.
   3.  Application has no information about the UE.  The Application
       contacts Network to validate the authentication result in the
       network stratum.  Application can find Network according the
       configuration or dynamical discovery protocol.
   4.  Network responds to Application with authentication result.
   5.  UE is authorized to access the Application.

   The message flows below make use of the security capabilities
   provided by network and some building blocks, such as GSS-API, AAA-
   SML etc.

   Editor's Note: The usage of GSS-EAP [I-D.ietf-abfab-gss-eap] in this
   case will be considered next time.

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     +------+         +--------+        +------+         +------+
     |  UE  |         |   NAS  |        |  IdP |         |  RP  |
     +---+--+         +----+---+        +---+--+         +---+--+
         |                 |                |                |
       +-+-----------------+----------------+-+              |
       |   1. Network Access Authentication   |              |
       +-+-----------------+----------------+-+              |
         | 2. Access Application            |                |
         +-------------------------------------------------->|
         |                 |                | 3. AAA Request |
         |                 |                |<---------------+
         |                 |                | 4. AAA Response|
         |                 |                +--------------->|
         |                 |                |        +-------+-------+
         |                 |                |        |5. Validate the|
         |                 |                |        |   Signature   |
         |                 |                |        +-------+-------+
         | 6. Establish Secure Channel      |                |
         |<--------------------------------------------------+
         |                 |                |                |

                        Figure 2: Message Flow - 1

   1.  When UE access network, UE is performed mutual authentication
       with network.  EAP can be utilized to faciliate the
       authentication procedure.  EAP-Identity and EAP-Method will be
       exchanged between UE and network element.  After sucessful
       authentication, an shared MSK is generated and stored in UE and
       IdP respectively, which can be used to authenticate other
       applications and then establish secure channels.
   2.  UE accesses Relying Party (RP).  UE is identified by NAI
       [RFC4282].  GSS-API [RFC4121] is acted as underlying transport
       mechanisms.  The required credential is derived from step 1.
   3.  When RP receieves the request from UE, it checkes whether the
       credential is avialable.  If not, RP initiates AAA request to
       retrieve credential from IdP [I-D.ietf-abfab-aaa-saml]
       [I-D.jones-diameter-abfab].
   4.  IdP constructs the SAML artefact by means of NAI and MSK
       generated in step 1.  AAA response with SAML message sends to RP.
   5.  RP validates the signature in the SAML message.
   6.  RP establishes secure channel with UE by means of GSS-API.

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     +------+         +--------+        +------+         +------+
     |  UE  |         |   BSF  |        |  IdP |         |  RP  |
     +---+--+         +----+---+        +---+--+         +---+--+
         |                 |                |                |
       +-+-----------------+----------------+-+              |
       |   1. Boostrapping Procedure          |              |
       +-+-----------------+----------------+-+              |
         | 2. Access Application            |                |
         +-------------------------------------------------->|
         |                 |                | 3. AAA Request |
         |                 |                |<---------------+
         |                 |                | 4. AAA Response|
         |                 |                +--------------->|
         |                 |                |        +-------+-------+
         |                 |                |        |5. Validate the|
         |                 |                |        |   Signature   |
         |                 |                |        +-------+-------+
         | 6. Establish Secure Channel      |                |
         |<--------------------------------------------------+
         |                 |                |                |

                        Figure 3: Message Flow - 2

   This case makes use of BSF (Boostrapping Server Function) defined in
   [TS33.220].  In Step 1, after the boostrapping procedure, a shared
   session key is generated between UE and IdP, which is used to
   authenticate UE by RP and establish secure channel between UE and RP.

   Step 2~6 is similar to procedures in Figure 2.

5.  Acknowledgements

   The author would like to thank Klaas Wierenga, Hannes Tschofenig, Sam
   Hartman, Rhys Smith, Tao Fu, Zhengxue Xia for their valuable
   comments.

6.  IANA Considerations

   TODO

7.  Security Considerations

   TODO

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8.  References

8.1.  Normative References

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

   [RFC4121]  Zhu, L., Jaganathan, K., and S. Hartman, "The Kerberos
              Version 5 Generic Security Service Application Program
              Interface (GSS-API) Mechanism: Version 2", RFC 4121,
              July 2005.

   [RFC4282]  Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The
              Network Access Identifier", RFC 4282, December 2005.

8.2.  Informative References

   [I-D.lear-abfab-arch]
              Howlett, J., Hartman, S., Tschofenig, H., and E. Lear,
              "Application Bridging for Federated Access Beyond Web
              (ABFAB) Architecture", draft-lear-abfab-arch-02 (work in
              progress), March 2011.

   [I-D.ietf-abfab-usecases]
              Smith, R., Tysom, M., and S. Cooper, "Application Bridging
              for Federated Access Beyond web (ABFAB) Use Cases",
              draft-ietf-abfab-usecases-00 (work in progress),
              March 2011.

   [I-D.ietf-abfab-aaa-saml]
              Howlett, J. and S. Hartman, "A RADIUS Attribute for SAML
              Messages", draft-ietf-abfab-aaa-saml-01 (work in
              progress), March 2011.

   [I-D.jones-diameter-abfab]
              Jones, M. and H. Tschofenig, "The Diameter 'Application
              Bridging for Federated Access Beyond Web (ABFAB)'
              Application", draft-jones-diameter-abfab-00 (work in
              progress), March 2011.

   [I-D.ietf-abfab-gss-eap]
              Hartman, S. and J. Howlett, "A GSS-API Mechanism for the
              Extensible Authentication Protocol",
              draft-ietf-abfab-gss-eap-04 (work in progress),
              October 2011.

   [GSMA_IDM]

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              GSM Association, "White paper on Identity Management
              Requirements, Issues, and Directions for Mobile Industry",
              August 2007, <http://wiki.projectliberty.org/images/d/d8/
              GSMA_IDM_WP-SE47.pdf>.

   [TelecoSiG]
              Liberty Alliance Project, "Bridging IMS and Internet
              Identity", December 2009, <http://www.projectliberty.org/
              liberty/content/download/4315/28869/file/
              WP-BridgingIMS_AndInternetIdentity_V1.0.pdf>.

   [TS33.220]
              3GPP, "Generic Authentication Architecture (GAA); Generic
              Bootstrapping Architecture (GBA)", 3GPP TS 33.220 10.0.0,
              October 2010.

   [TR33.980]
              3GPP, "Liberty Alliance and 3GPP security interworking;
              Interworking of Liberty Alliance Identity Federation
              Framework (ID-FF), Identity Web Services Framework (ID-
              WSF) and Generic Authentication Architecture (GAA)", 3GPP
              TR 33.980 10.0.0, April 2011.

   [TR33.924]
              3GPP, "Identity management and 3GPP security interworking;
              Identity management and Generic Authentication
              Architecture (GAA) interworking", 3GPP TR 33.924 10.1.0,
              June 2011.

Author's Address

   Yinxing Wei (editor)
   ZTE Corporation
   No 68, Zijinghua Road
   Nanjing, Jiangsu  210012
   China

   Phone: +86 25 52872328
   Email: wei.yinxing@zte.com.cn

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