Handover Keys using AAA (draft-vidya-mipshop-fast-handover-aaa-01.txt) Vidya Narayanan Narayanan Venkitaraman Hannes Tschofenig Gerardo Giaretta Julien Bournelle November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01

draft-vidya-mipshop-fast-handover-aaa-01 Example Topology AP2.1 MN AP2.2 AR2 AAAH Server AP1.1 AR1 MN AP1.2 Objective is to create a shared key between MN and AR using AAA November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01

Protocol Overview AAA Server MN AR1 AR2 HKReq RADIUS Access Request HMK Generated HMK Generated HKReq ([MN ID, Msg ID, Seq #, CoA], MN-AAA Auth Option) RADIUS Access Request ([[MN ID, Msg ID, Seq #, CoA], MN-AAA MAC, NAS IP], AR-AAA MAC) Validate MAC Generate HK1 RADIUS Access Accept ([Nonce, Lifetime] MN-AAA Auth Option, [HK1], ARn-AAA Key) HKResp Decrypt HK1 Generate HK1 ([Nonce, Lifetime] MN-AAA Auth Option) MN Handoff To AR2 FNA([FBU], HK1) [FBU], HK1 Validate FBU FBAck FBAck November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01

Protocol Overview – Salient Points Handover Master Key (HMK) shared between MN and AAAH May be derived using EAP AMSK at time of power-up or first network access HMK derived at the MN and AAA (EAP) Server Not transported anywhere else May be a pre-shared key between MN and AAAH Handover Key (HK) Derivation HK = HMAC-SHA1(HMK, AR ID | MN ID | AAA-MN Nonce, “Handover Key”) HK derived with each AR AR verifies MN CoA and binds it to the HK HK may be derived indirectly with another AR through current AR May be needed to derive a new key with a given AR after lifetime expires E.g. pre-authentication before handoff Lifetime value provided by AAA server; enforced by AR and MN MN verifies HK with AR after handoff if pre-authentication was used Used to bind HK to CoA of MN and to verify key is valid at AR The protocol is similar to the MIP-AAA model November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01

Additions/Changes since last version Moved from UDP-based to Mobility Header type HKReq and HKResp are now new MH types Allows re-use of many already defined mobility options Follows the model of FMIP control messages Address Validation/Binding Added details on CoA validation Highlights of the procedure AR performs NDP upon receiving HKReq with a non-NULL CoA Message ID from HKReq added in the NS from AR as an option MN that sent HKReq MUST NOT respond with NA Address validated if no other response is received for the NS Procedure similar to AR performing PND upon receiving HI or FNA The AR *may* use other available means of address validation (as it may do so for the HI/FNA processing) November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01

draft-vidya-mipshop-fast-handover-aaa-01 To-Dos Derivation of Handover Master Key using EAP Key Hierarchy Targeting separate I-D on the topic (use Appendix A in draft as basis) Need EAP WG to solidify AMSK definition RADIUS Attributes Definition Targeting separate I-D on the topic (use Appendix B in draft as basis) Diameter AVPs/Application Definition Need to investigate possible re-use of NASREQ application Targeting separate I-D on the topic (use Appendix C in draft as basis) November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01

MN-AR Authentication Option (draft-narayanan-mn-ar-auth-option-00) Defines a new Mobility Sub-option for carrying MN-AR Authentication Data Based on the “Authentication Protocol for MIP6” Protocol Gist: Authentication Data = First (96, HMAC_SHA1(MN-AR Shared key, Mobility Data)) Mobility Data = care-of address | home address | MH Data Used in draft-vidya-handover-keys-aaa-01 to include MN-AR Auth Data in HKReq/HKResp Also suitable for carrying MN-AR Auth Data in FBU/FBAck in FMIPv6 Concerns on the dependency on information document Raised on ML Technically, the re-use makes sense Integrate into 4068bis? November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01

draft-vidya-mipshop-fast-handover-aaa-01 Accept as WG item? QUESTIONS? November 7, 2005 draft-vidya-mipshop-fast-handover-aaa-01