1. 1 IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-11-0164-03-0sec Title: ERP proposal Date Submitted: October 13, 2011 Authors or Source(s): Fernando Bernal-Hidalgo, Rafa Marín-López Abstract: Modifications to be carried out in current D04 related with comment #24.

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3. MIAK (Media Independent Authentication Key) A new key named MIAK needs to be derived to generate the AUTH TLV. Modify figure 33, including the MIAK to left of the MIIK. Basically, selecting a suitable value for L in KDF defined in section 9.2.2, we can obtain MIAK. We will set MIAK length to 128 bits.

4. AUTH TLV Generation How to generate the AUTH TLV – PRF(K, “AUTH_TLV” | MIH_AUTH message| MNCiphersuite | PoSCiphersuite) K = MIAK MIH_AUTH message: The whole MIH_AUTH message including AUTH TLV filled with 0s. MNCiphersuite = the ciphersuite sent by the MN PoSCiphersuite = the ciphersuite sent by the PoS PRF is the one selected in the KDF_LIST – KDF_CMAC_AES – KDF_HMAC_SHA1 – KDF_HMAC_SHA256 PRF output length = it will depend on the negotiated PRF

5. Draft Modifications Rename – Change KDF_LIST to PRF_LIST Modify definition – PRF_LIST Bit 0: KDF_AES_CMAC  PRF_AES_CMAC Bit 1: KDF_HMAC_SHA1  PRF_HMAC_SHA1 – We missed KDF_HMAC_SHA256. Add it: Bit 2 : KDF_HMAC_SHA256  PRF_HMAC_SHA256

6. DICUSSION Should the MIH Service Authentication Phase be protected by an existing MIH SA during re-authentication with the same PoS? – We believe that MIH_AUTH messages should be always protected by using AUTH TLV  To not use MIH SA How is AUTH TLV generated (key used and ciphersuite)? – Done Should we add a new section explaining how downgrading attack is avoided? – No. Nevertheless, the way how AUTH TLV is generated solves the problem. – Inconsistency since PoS does not receive a key confirmation from the MN  Add an addtional MIH_AUTH exchange.

7. ERP MN Initiated MIH Access Authentication Phase EAP Peer MN EAP Peer MN EAP Auth. PoS EAP Auth. PoS MIH_Auth request (EAP-Initiate/Re-Auth, parameters) MIH_Auth response (EAP-Finish/Re-Auth, selections) MIH Capability Discovery Request MIH Capability Discovery Response MIH Termination Request MIH Termination Response... Capability Discovery Phase MIH Service Authentication Phase Service Access Phase Termination Phase MIH_Auth request (AUTH) MIH_Auth response (AUTH)

8. ERP Network Initiated (1) MIH Access Authentication Phase EAP Peer MN EAP Peer MN EAP Auth. PoS EAP Auth. PoS MIH_Auth request (EAP-Initiate/Re-Auth, parameters) MIH_Auth response (EAP-Finish/Re-Auth, selections) MIH_Auth indication (EAP-Initiate/ Re-auth-Start) Trigger MIH Capability Discovery Request MIH Capability Discovery Response Capability Discovery Phase MIH Termination Request MIH Termination Response... Service Access Phase Termination Phase MIH Service Authentication Phase MIH_Auth request (AUTH) MIH_Auth response (AUTH)

9. ERP Network Initiated (2) MIH Access Authentication Phase EAP Peer MN EAP Peer MN EAP Auth. PoS EAP Auth. PoS MIH_Auth request (EAP-Request/Identity) Trigger MIH_Auth response MIH Service Authentication Phase MIH Capability Discovery Request MIH Capability Discovery Response Capability Discovery Phase MIH Termination Request MIH Termination Response... Service Access Phase Termination Phase MIH_Auth request (EAP-Initiate/Re-Auth, parameters) MIH_Auth response (EAP-Finish/Re-Auth, selections) MIH_Auth request (AUTH) MIH_Auth response (AUTH)