1. Authentication and Key Management of MP with multiple radios
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Authentication and Key Management of MP with multiple radios
Date:
Authors:
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

2. Month Year
doc.: IEEE yy/xxxxr0
July 2008
Abstract
This presentation states the CID #504 from LB126, the secure association setup problem when the multiple radios MP joins into the mesh network, and the suggested solution including the summary text change of the draft.
CID#504: PMK-MKD which is derived after the higher-layer authentication should only be related with the authentication credential and some other device information , not tighten-related with the MAC address of a radio. It would induce multiple authentication problems when the mesh node has two or more radios
解决什么问题 多radio的重复认证问题
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

3. Agenda Problem Statement Resolution July 2008 Month Year
doc.: IEEE yy/xxxxr0
July 2008
Agenda
Problem Statement
Resolution
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

4. Current Secure association setup mechanism
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Current Secure association setup mechanism
Supplicant
Step2:
After MP authenticates with AS through MKD
PMK-MKD and MKDK will be derived
Bind with SPA
Multiple initial authentication procedures should be request for multi-radio MP because each radio will has each SPA.
Mesh Authenticator
Step1: Authentication Method & Role & Key Management type Negotiation
Probe/Beacon
Peer Link Management
Step2:Authentication through MKD & The key hierarchy setup
Initial Authentication if needed
Step3: PTK/GTK distribution
4-Way handshake to build session keys
Secure communication
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

5. Current 802.11s Key Hierarchy
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Current s Key Hierarchy
The PMK-MKD and MKDK are bound with SPA.
MeshTopLevelKeyData = KDF-768(XXKey, “Mesh Key Derivation”,MeshID, MKD-NAS-ID, MKDD-ID, SPA)
There will be multiple SPAs for a multi-radio Supplicant MP; hence there will be multiple PMK-MKDs and MKDKs
Multiple initial authentication procedures should have to be launched.
Held by MKD, Supplicant & MA
PMK-MA=KDF-256(PMK-MKD,”MA Key Derivation”, PMK-MKDName|| MA-ID|| SPA)
MSK/PSK
Held by MKD & Supplicant
PMK-MKD = L(MeshTopLevelKeyData, 0, 256)
Held & Derived by Supplicant & MA
PTK=KDF(PMK-MA,”Mesh PTK key derivation”,MPTKSNonce|| MPTKANonce|| MA-ID||SPA||PMK-MAName)
Held by Supplicant & MKD
MKDK = L(MeshTopLevelKeyData, 384, 256)
Held & Derived by Supplicant & MKD, deliver PMK-MA
MPTK-KD=KDF-256(MKDK, “Mesh PTK-KD Key”,MA-Nonce||MKD-Nonce||MA-ID||MKD-ID)
PMK-MA
PMK-MKD
PTK
MKDK
MPTK-KD
Key Distribution branch
Link Security Branch
Suggestions: MPTK-KD = KDF-256(MKDK, “Mesh PTK-KD Key”, MeshID, MKD-NASID, MKD-ID, Dev_ID, MA-Nonce, MKD-Nonce)
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

6. Disadvantages of multiple authentications
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Disadvantages of multiple authentications
Can not detect the authentication credential is used for different MPs or different radios in the same MP simultaneously.
The authentication credential may be used by multiple MPs simultaneously.
Increase the air cost overhead when launching multiple times initial authentication
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

7. The root of the above problem
Month Year
doc.: IEEE yy/xxxxr0
July 2008
The root of the above problem
The EAP authentication should occur between the peer and EAP server
The low layer identity should only identify the supplicant
There are multiple MAC addresses in multi-radio MP which can not only identify MP
Each radio each MAC address
Clarify how to only identify the MP
The link security association should bind tightly with the MAC address which identify the wireless radio module.
The radio’s MAC address should still be used to derive PTK
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

8. Agenda Problem Statement Resolution July 2008 Month Year
doc.: IEEE yy/xxxxr0
July 2008
Agenda
Problem Statement
Resolution
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

9. Solution Requirements
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Solution Requirements
The initial authentication should only be launched once when an MP join the mesh network, no matter how many radios it has.
Authentication credential is issued one MP device
One PMK-MKD and one MKDK for an MP, shared by all the radios
Different radio in the same MP should use different PTK.
Distribute keys for radios of the device through one time initial authentication procedure
There should be one MPTK-KD between an MA and MKD.
The communication between MKD and MP is not tied to a peer link with MAC addresses
Less modification, more better.
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

10. Possible solution July 2008 Clarify two identifiers
Month Year
doc.: IEEE yy/xxxxr0
Possible solution
July 2008
Clarify two identifiers
MP-ID: six bytes to only identify the MP node. It may use one of the MAC address of the MP if there are more than one PHY.
MPA: the MAC address of the communicating radio module of the MP.
Three roles when MP doing authentication and key hierarchy, and different ID names to identify the roles which actually is ‘MP-ID’.
Amend the current security solution defined in D2.0
Bind PMK-MKD ,MKDK and PMK-MA to SP-ID instead of SPA
MeshTopLevelKeyData = KDF-768(XXKey, “Mesh Key Derivation”,MeshID, MKD-NAS-ID, MKDD-ID, SPA SP-ID)
Only one MPTK-KD between an MA and MKD
The key is to protect the communication between the two node entities, not the link level
PTKs should bind with peer link MAC addresses
Rename the ‘MA-ID’ into ‘MAA’ (Mesh Authenticator Address), because the MAA has the same definition of ‘MA-ID’ in s D2.0
MP-ID
MPA
Supplicant
SP-ID
SPA
Authenticator
MA-ID
MAA
MKD
MKD-ID
N\A
MA-ID: the MAC address of the MA; it is the one of the MAC address of the MA if it has more than one PHY.
MKD-ID: the MAC address of the MKD; it is the one of the MAC address of the MKD if it has more than one PHY.
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

11. Peer Link Management negotiation clarify
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Peer Link Management negotiation clarify
MP1
MP2
Get the MP-ID besides the radio MAC address (MPA)
The MP-ID is used to do the selector MP determination
Do not use MPA, because there are multiple MPAs which can not only identify the MP.
Link instance is still bound with MPAs
<local MPA, peer MPA, local ID, peer ID>
I’m MP-ID#1, MPA#1, Who are u?
I have PMK-MA#1 ...
I’m MP-ID#2, MPA#2, Who are u?
I have PMK-MA#1, PMK-MA#
PMK-MA negotiation
by MP-ID
Role negotiation
PMK-MA negotiation
by MP-ID
Role negotiation
I’m supplicant, use PMK-MA#1
维护MP-ID和MPA的映射关系
MP之间可以区分设备之间的链路连接情况
两个设备之间是否能建立多个link依赖于于各系统的实现
OK, I’m authenticator,
I could use PMK-MA#1 ...
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

12. Initial authentication clarify
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Initial authentication clarify
Supplicant MP uses PLM to tell the SP-ID to MA in MSAIE and trigger the initial authentication procedure
MA transfers the SP-ID to MKD in Mesh EAP encapsulation frame
Supplicant MP and MKD use SP-ID to derive the PMK-MKD, MKDK, PMK-MA and to request PMK-MA AS
Sup MP MA
MKD
2. EAPOL (EAP-Request Identity)
3. EAPOL (EAP-Response Identity)
5. EAP Transport (EAP-Response Identity)
7. EAP Transport (EAP-Success, MSK)
9. EAPOL (EAP-Success)
1. EAPOL-Start
4. Mesh EAP encapsulation (SPA, SP-ID)
Derive Pairwise Key (PMK-MKD, MKDK, PMK-MA)
8. Mesh EAP encapsulation(EAP-Response)
6. EAP-specific (mutual) authentication
Peer Link Open (Request Authentication, SPA, SP-ID)
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

13. 802.11s Key Hierarchy Clarify
Month Year
doc.: IEEE yy/xxxxr0
July 2008
802.11s Key Hierarchy Clarify
MAA: the authenticator MP’s MAC address
SP-ID: the identifier of the Supplicant MP; it is the one of the MAC address of the Supplicant MP if it has more than one PHY.
MA-ID: the identifier of the MA; it is one of the MAC addresses of the MA if it has more than one PHY.
MKD-ID: the identifier of the MKD; it is the one of the MAC address of the MKD if it has more than one PHY
MeshTopLevelKeyData = KDF-768(XXKey, “Mesh Key Derivation”,MeshID, MKD-NAS-ID, MKDD-ID, SPASP-ID)
Bind with MPs
Held by MKD, Supplicant & MA
PMK-MA=KDF-256(PMK-MKD,”MA Key Derivation”, PMK-MKDName|| MA-ID||SPA SP-ID)
MSK/PSK
Held by MKD & Supplicant
PMK-MKD = L(MeshTopLevelKeyData, 0, 256)
Bind with Radios
Held & Derived by Supplicant & MA
PTK=KDF(PMK-MA,”Mesh PTK key derivation”,MPTKSNonce|| MPTKANonce|| MA-ID MAA||SPA||PMK-MAName)
Held by Supplicant & MKD
MKDK = L(MeshTopLevelKeyData, 384, 256)
Held & Derived by Supplicant & MKD, deliver PMK-MA
MPTK-KD=KDF-256(MKDK, “Mesh PTK-KD Key”,MA-Nonce||MKD-Nonce||MA-ID||MKD-ID)
PMK-MA
PMK-MKD
PTK
MKDK
MPTK-KD
Key Distribution branch
Link Security Branch
Suggestions: MPTK-KD = KDF-256(MKDK, “Mesh PTK-KD Key”, MeshID, MKD-NASID, MKD-ID, Dev_ID, MA-Nonce, MKD-Nonce)
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

14. Summary updated text of the Draft
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Summary updated text of the Draft
New Abbreviations:
MP-ID: Mesh point Identifier
MPA: Mesh Point Address
Change the SPA into SP-ID when deriving the MKDK ,PMK-MKD and PMK-MA.
Change the MA-ID into MAA when deriving the PTK.
Change the criterion of selector MP
Add the local MP-ID subfield in MSA IE in order to let the pair MPs know the identities of each other.
Change the SPA into SP-ID in EAP Authentication field to send the SP-ID to MKD.
Extend the definition of MA-ID and MKD-ID to support multiple radios MP.
Element ID
Length
Handshake Control
Local MP-ID
MA-ID
Selected AKM Suite
Selected Pairwise Cipher Suite
Chosen PMK
Local Nonce
Peer Nonce
Optional Parameters
Encapsulation Type
Replay Counter
SPA SP-ID
EAP Message Length
EAP Message
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

15. Summary updated text of the Draft(cont’)
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Summary updated text of the Draft(cont’)
Change the SPA into SP-ID in Mesh Key Transport Control field when requesting the PMK-MA
PMK-MKDName
SPA SP-ID
Replay Counter
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

16. Conclusion Less modification, more efficiency
Month Year
doc.: IEEE yy/xxxxr0
July 2008
Conclusion
Less modification, more efficiency
Add the ‘MP-ID’ to only identify the MP, especially for the multiple radio MPs, and hence the SP-ID, MA-ID, MKD-ID when the MP is in different roles.
Extend the definition of MA-ID and MKD-ID to be an unique identify of the MP devices, which are more reasonable to be named as an identifier also.
Add the local MP-ID(6 bytes) field in MSA IE to let the pair MPs know the identities of each other when building the link.
Rename the ‘MA-ID’ to ‘MAA’ in PTK derivation formula to make the PTK bind with peer links
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

17. Reference Draft_P802.11s_D2.00 July 2008 Month Year
doc.: IEEE yy/xxxxr0
July 2008
Reference
Draft_P802.11s_D2.00
Charles Fan,Amy Zhang, Huawei
John Doe, Some Company

18. July 2008
Motion
Moved, To adopt the normative text in 11-08/526r5 resolving CID 504 and direct the Editor to incorporate it into the Draft.
Moved:
Second:
Result:
Charles Fan,Amy Zhang, Huawei