Mobile IP Working Group Charles E. Perkins INTERNET DRAFT Nokia Research Center 14 July 2000 Pat R. Calhoun Sun Microsystems Laboratories Generalized Key Distribution Extensions for Mobile IP draft-perkins-mobileip-gen-key-02.txt Status of This Memo This document is a submission by the mobile-ip Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the MOBILE-IP@STANDARDS.NORTELNETWORKS.COM mailing list. Distribution of this memo is unlimited. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at: http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at: http://www.ietf.org/shadow.html. Abstract Recent proposals have suggested several kinds of key extensions for Mobile IP registration messages. These keys may be used between the mobile node and mobility agents, or between the mobility agents themselves. This document specifies generalized extension formats that can be useful for several kinds of key distributions. Each generalized extension format will have subtypes which indicate the specific format for the key distribution data. Perkins, Calhoun Expires 14 January 2001 [Page i] Internet Draft Generalized Key Extensions 14 July 2000 1. Introduction Recent proposals [5, 1, 6] have suggested several kinds of key extensions for Mobile IP [4] registration messages. These keys may be used between the mobile node and mobility agents, or between the mobility agents themselves. This document specifies generalized extension formats that can be useful for several kinds of key distributions. Each generalized extension format will have subtypes which indicate the specific format for the key distribution data. Each generalized format conforms to the overall format suggested for generalized Mobile IP extensions recently described for MIER [2]. Different generalized extensions are defined depending upon the following factors: - The intended use of the key - Whether the extension requests a key or supplies a key 2. Generalized MN-FA Key Request Extension Figure 1 illustrates the Generalized MN-FA Key Request Extension. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Subtype | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mobile Node SPI | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MN-FA Key Request Subtype Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: The Generalized Mobile IP MN-FA Key Request Extension Type 40 (not skippable) (see [4]) Subtype a number assigned to identify the way in which the Key Request Data is to be used when generating the registration key Length 4 plus the number of bytes in the Subtype Data; SHOULD be at least 20. Perkins, Calhoun Expires 14 January 2001 [Page 1] Internet Draft Generalized Key Extensions 14 July 2000 Mobile Node SPI The Security Parameters Index that the mobile node will assign for the security association created for use with the registration key. MN-FA Key Request Subtype Data Data needed to carry out the creation of the registration key on behalf of the mobile node. 3. Generalized MN-FA Key Reply Extension The Generalized MN-FA Key Reply extension supplies a registration key requested by using one of the subtypes of the Generalized MN-FA Key Request extension. Figure 2 illustrates the format Generalized MN-FA Key Reply Extension. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Subtype | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Key Reply Subtype Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: The Generalized Mobile IP MN-FA Key Reply Extension Type 41 (not skippable) (see [4]) Subtype a number assigned to identify the way in which the Encoded MN-FA Key Data is to be decrypted to obtain the registration key Length The 16-bit Length field indicates the length of the extension. It is equal to 4 plus the number of bytes in the Encoded MN-FA Key Data. MN-FA Key Reply Subtype Data An encoded copy of the key to be used between the mobile node and the foreign agent, along with any other information needed by the recipient to create the designated Mobility Security Association. Perkins, Calhoun Expires 14 January 2001 [Page 2] Internet Draft Generalized Key Extensions 14 July 2000 For each subtype, the format of the MN-FA Key Reply Subtype Data has to be separately defined according to the particular method required to set up the security association. In some cases, the MN-FA Key supplied in the data for a subtype of this extension comes by a request which was sent using a subtype of the Generalized MN-FA Key Request Extension. In that case, the SPI to be used when employing the security association defined by the registration key is the same as given in the original request. 4. Generalized MN-HA Key Reply Extension 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Subtype | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MN-HA Key Reply Subtype Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: The Generalized Mobile IP MN-HA Key Reply Extension Type 43 (not skippable) (see [4]) Subtype a number assigned to identify the way in which the Encoded MN-HA Key Data is to be decrypted to obtain the registration key Length The 16-bit Length field indicates the length of the extension. It is equal to 4 plus the number of bytes in the Encoded MN-HA Key Data. Lifetime This field indicates the duration of time (in seconds) for which the MN-HA key is valid. MN-HA Key Reply Subtype Data An encrypted copy of the key to be used between the mobile node and its home agent, along with any other information needed by the mobile node to create the designated Mobility Security Association with the home agent. Perkins, Calhoun Expires 14 January 2001 [Page 3] Internet Draft Generalized Key Extensions 14 July 2000 For each subtype, the format of the MN-HA Key Reply Subtype Data has to be separately defined according to the particular method required to set up the security association. 5. Generalized FA-HA Key Reply Extension 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Subtype | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FA-HA Key Reply Subtype Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: The Generalized Mobile IP FA-HA Key Reply Extension Type 45 (not skippable) (see [4]) Subtype a number assigned to identify the way in which the Encoded FA-HA Key Data is to be decrypted to obtain the registration key Length The 16-bit Length field indicates the length of the extension. It is equal to 4 plus the number of bytes in the Encoded FA-HA Key Data. Lifetime This field indicates the duration of time (in seconds) for which the FA-HA key is valid. FA-HA Key Reply Subtype Data An encrypted copy of the key to be used between the foreign agent and the mobile node's home agent, along with any other information needed by the foreign agent to create the designated Mobility Security Association with that home agent. For each subtype, the format of the FA-HA Key Reply Subtype Data has to be separately defined according to the particular method required to set up the security association. 6. Generalized FA-FA Key Reply Extension Perkins, Calhoun Expires 14 January 2001 [Page 4] Internet Draft Generalized Key Extensions 14 July 2000 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Subtype | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FA-FA SPI | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FA-FA Key Reply Subtype Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: The Generalized Mobile IP FA-FA Key Reply Extension Type 46 (not skippable) (see [4]) Subtype a number assigned to identify the way in which the Encoded FA-FA Key Data is to be decrypted to obtain the registration key Length The 16-bit Length field indicates the length of the extension. It is equal to 4 plus the number of bytes in the Encoded FA-HA Key Data. FA-FA SPI This field indicates the SPI that should be used to decipher the FA-FA key. FA-FA Key Reply Subtype Data An encrypted copy of the key to be used between the foreign agent and its home agent, along with any other information needed by the mobile node to create the designated Mobility Security Association with the home agent. For each subtype, the format of the FA-HA Key Reply Subtype Data has to be separately defined according to the particular method required to set up the security association. 7. IANA Considerations Each generalized extension specified in this document is to be numbered from the space of Mobile IP registration extension numbers defined in RFC 2002 [4] as extended in RFC 2356 [3]. The numbers 40, 41, 43, and 45 chosen in the text are currently unassigned. A subtype address space must be created for each generalized extension defined in this document. From this space, subtype values Perkins, Calhoun Expires 14 January 2001 [Page 5] Internet Draft Generalized Key Extensions 14 July 2000 will be assigned according to standards approved principally by the mobile-ip working group, but other working groups may also submit requests to assign subtype numbers for Mobile IP extensions. 8. Security Considerations The extensions in this document are intended to provide the appropriate level of security for Mobile IP entities (mobile node, foreign agent, and home agent) to operate Mobile IP registration protocol. The security associations resulting from use of these extensions do not offer any higher level of security than what is already implicit in use of the security association between the receiver and the entity distributing the key. References [1] P. Calhoun, Haseeb Akhtar, Emad Qaddoura, and N. Asokan. Minimal Latency Secure Hand-off. draft-calhoun-mobileip-min-lat-handoff-01.txt, February 2000. (work in progress). [2] M. Khalil, R. Narayanan, H. Akhtar, and E. Qaddoura. Mobile IP Extensions Rationalization (MIER). Internet Draft, Internet Engineering Task Force. draft-ietf-mobileip-mier-03.txt, February 2000. Work in progress. [3] G. Montenegro and V. Gupta. Sun's SKIP Firewall Traversal for Mobile IP. Request for Comments (Informational) 2356, Internet Engineering Task Force, June 1998. [4] C. Perkins. IP Mobility Support. Request for Comments (Proposed Standard) 2002, Internet Engineering Task Force, October 1996. [5] C. E. Perkins and P. Calhoun. AAA Registration Keys for Mobile IP. draft-ietf-mobileip-aaa-key-01.txt, January 2000. (work in progress). [6] C. E. Perkins and D. Johnson. Registration Keys for Route Optimization. draft-ietf-mobileip-regkey-01.txt, February 2000. (work in progress). Perkins, Calhoun Expires 14 January 2001 [Page 6] Internet Draft Generalized Key Extensions 14 July 2000 Addresses The working group can be contacted via the current chairs: Basavaraj Patil Phil Roberts Nokia Corporation Motorola 6000 Connection Drive 1501 West Shure Drive M/S M8-540 Irving, TX 75039 Arlington Heights, IL 60004 USA USA Phone: +1 972-894-6709 Phone: +1 847-632-3148 Fax : +1 972-894-5349 EMail: Raj.Patil@nokia.com EMail: QA3445@email.mot.com Questions about this memo can also be directed to the authors: Charles E. Perkins Pat R. Calhoun Communications Systems Lab Network & Security Center Nokia Research Center Sun Microsystems Laboratories 313 Fairchild Drive 15 Network Circle Mountain View, California 94043 Menlo Park, California 94025 USA USA Phone: +1-650 625-2986 Phone: +1 650-786-7733 EMail: charliep@iprg.nokia.com EMail: pcalhoun@eng.sun.com Fax: +1 650 625-2502 Fax: +1 650-786-6445 Perkins, Calhoun Expires 14 January 2001 [Page 7]