Federated Cross-Layer Access
draft-wei-abfab-fcla-01
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| 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.
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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
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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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