Handover Keying (hokey)

Last modified: 2012-08-01

Chairs

Security Area Director(s)

Security Area Advisor

Mailing Lists:

General Discussion: hokey@ietf.org
Archive: http://www.ietf.org/mail-archive/web/hokey/

Description of Working Group:

A mobile device has to re-authenticate each time it changes its point of attachment to the network. When it goes through the full procedure of authentication it creates a series of ruptures, during which the medium cannot flow. This results in a poor user experience during handover. However, it is possible to shorten the time it takes to re-authenticate by reusing the key information developed during the initial authentication.

The Handover Keying Working Group is concerned with developing procedures for key reuse and delivery, while respecting good security practice. The Handover Keying Working Group has already done work on this subject, but it has not yet developed the complete set of procedures, protocols, and changes needed for different security environment scenarios and situations.

The solutions specified by the HOKEY WG fall into several categories, based on timing and mechanism. The authentication and key management may occur before handoff, when latency is much less critical. Alternatively, authentication and key management can occur as part of the handoff, where latency is critical. Solutions should reduce or eliminate the number of referrals to AAA servers, and solutions should avoid re-executing lengthy EAP method exchanges. This may be accomplished by providing new mechanisms for cryptographic keying material in combination with a protocol for the timely delivery of appropriate keys to the appropriate entities. Solutions are expected to include "handover keying," "low-latency re-authentication,"
and "pre-authentication" or "early authentication".

All solution categories are useful, each supporting different scenarios. The HOKEY WG may provide multiple solutions, each addressing a different scenario.

Solutions specified by the HOKEY WG must:

1) Be responsive to handover and re-authentication latency performance objectives within a mobile wireless access network.

2) Fulfill the requirements in RFC 4962 and RFC 5247.

3) Be independent of the access-technology. Any key hierarchy topology or protocol defined must be independent of EAP lower layers. The protocols may require additional support from the EAP lower layers that use it.

4) Accommodate inter-technology heterogeneous handover and roaming.

5) Not require changes to EAP methods. Any extensions defined to EAP must not cause changes to existing EAP methods.

In specifying an access-technology-independent solution, media independent guidelines for SDOs may also be needed to explain how the keying material and signaling can be employed in a specific access technology.

HOKEY WG Deliverables
=====================

1) A specification of Local Domain Name Discovery for ERP. Currently the use of DHCP mechanisms to request the local domain name is unspecified. There are other useful scenarios that need to be addressed. Lower layer announcement for local domain name is unspecified. Ambiguity with using initial full EAP exchange for re-authentication needs to be clarified. Additional re-authentication scenarios, for which there is interest, need to be addressed.

2) A specification of Early Authentication solutions. These include use of EAP to pre-establish authenticated keying material on a target authenticator prior to arrival of the peer.

3) A specification for a Hokey architecture Document. It includes deployment of ERP and EAP early authentication protocol in the mobile environment. There are various useful scenarios that need to be addressed. This specification and the revision of RFC5296 should be conducted in parallel.

4) Assistance to the 802.21a group in specifying the integration of EAP pre-authentication with IEEE 802.21a. The Hokey Working Group shall perform tasks that are complementary to and do not duplicate work being done in IEEE 802.21a.

6) A specification for NAS-Authenticator interaction. NAS interaction can be used to release resources in the old NAS and achieve faster initiation of authentication. Related work in external SDOs on authenticator/NAS interaction for re-authentication may be taken into consideration.

7) A revision of RFC 5296 to eliminate unnecessary references to the home server.

8) Assistance to the radext and dime Working Groups in developing AAA support for handoff keying.

Goals and Milestones

Done First draft with a problem statement on EAP re-authentication and key management
Done First draft on EMSK-based Keying Hierarchy
Done First draft on EAP Re-authentication and Handover Keying Hierarchy
Done First draft on EAP Re-authentication Protocol
Done First draft on Protocol and Keying Hierarchy for Visited Domain Handovers and Re-authentication
Done Submit EMSK-based Keying Hierarchy draft to IESG
Done First draft on Handover Key Distribution Protocol
Done Submit the problem statement draft to IESG
Done Submit EAP Re-authentication and Handover Keying Hierarchy draft to IESG
Done Submit EAP Re-authentication Protocol draft to IESG
Done Submit Protocol and Keying Hierarchy for Visited Domain Handovers and Re-authentication draft to IESG
Done First draft on EAP Pre-authentication Specification for inter-technology and inter-domain handoffs
Done First draft on Local Domain Name Discovery for ERP
Nov 2009 First draft on Early Authentication solutions
Mar 2010 First draft on Hokey architecture
Mar 2010 First draft on NAS-Authenticator Interaction
Jul 2010 First draft on revision of RFC 5296
Mar 2011 Submit the Local Domain Name Discovery for ERP draft to IESG
Mar 2011 Submit the Early Authentication solutions draft to IESG
Jul 2011 Submit the NAS-Authenticator Interaction draft to IESG
Nov 2011 Submit the Hokey architecture draft to IESG
Nov 2011 Submit the revision of RFC 5296 to IESG
Mar 2012 Re-charter or shut down WG

No Internet-Drafts

Request for Comments