Handover Keys using AAA (draft-vidya-mipshop-fast-handover-aaa-01.txt)

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

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

3. Protocol Overview AAA Server MN AR1 AR2 HMK Generated HMK Generated HKReq RADIUS Access Request ([MN ID, Msg ID, Seq #, CoA], MN-AAA Auth Option) ([[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 ([Nonce, Lifetime] MN-AAA Auth Option) Generate HK1 MN Handoff To AR2 FNA([FBU], HK1) [FBU], HK1 Validate FBU FBAck FBAck draft-vidya-mipshop-fast-handover-aaa-01

4. 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 draft-vidya-mipshop-fast-handover-aaa-01

5. 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) draft-vidya-mipshop-fast-handover-aaa-01

6. 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) draft-vidya-mipshop-fast-handover-aaa-01

7. 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? draft-vidya-mipshop-fast-handover-aaa-01

8. Accept as WG item? QUESTIONS? draft-vidya-mipshop-fast-handover-aaa-01