doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide s Security concepts Jasmeet Chhabra, Intel Anand R Prasad, DoCoMo Euro-Labs Jesse Walker, Intel Hindenori Aoki, NTT DoCoMo

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Outline Goals Requirements Assumptions Basic security model Distributed Authentication Centralized Authentication Conclusion

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Goals/Requirements Reuse/build on top of current i techniques –802.11s PAR, Clause 18: “The amendment shall utilize IEEE i security mechanisms, or an extension thereof...” Other requirements –Allow peer-to-peer association/authentication between mesh points/mesh APs –Protect mesh management and control messages exchanged between mesh points/mesh APs (e.g. routing and topology info) –Allow mesh nodes to broadcast to all its neighbors : needed by routing services etc. –Maintain 11i data security for data delivery across multi-hop mesh path –Credentials issued might have to differentiate between a mesh point and a non-mesh point –Allow for both distributed and centralized authentication schemes

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Assumptions Authenticated Mesh Points in an administrative domain can be trusted for faithful forwarding of messages. –No selective forwarding like attacks –No eavesdropping

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Background i “Figure 16—Example 4-Way Handshakes in an IBSS”

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Basic security model New mesh point ESS Mesh Security bubble Supplicant Authenticator Group key is used for broadcast communications Pair-wise keys are used for unicast communications Authentication server could be distributed or centralized –Does not effect basic security model

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Basic security model (Contd.) Each mesh point supports both supplicant and authenticator functionality Each mesh point acts as supplicant and authenticator for each of its neighbors –Similar to IBSS security model in i After authentication/authorization/4-way handshake: –Mesh point uses its own group key to broadcast/multicast – Pair-wise key for unicast Number of keys is O (num_neighbors)

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Advantages Minimal changes required to i –Mainly language changes –Re-uses the strong and well debated solution Builds on top of current i standard Key management Complexity is controlled –O(num_neighbors)

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Authenticator Security model with stations ESS Mesh Security bubble Supplicant Access Point No change in the current STA operation

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Authentication Schemes IEEE i does not specify where the authentication server resides. –Can be on the AP/Node itself –Only specifies functionality needed As mentioned earlier, the authentication scheme could be –Distributed or –Centralized

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Distributed authentication Completely distributed: automatic or manual configuration of nodes Elect: Requires solution for the case where elected AS becomes unavailable –A node is assigned as AS at random –The first node becomes AS –Some other mechanism is used Select: The user selects a node as AS

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Centralized Authentication The centralized method involves a ESS mesh AP that has access to a AS The AS could either reside locally or could be placed elsewhere in the network All other ESS mesh APs and STAs will be authenticated via the AP connected to the AS

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Open questions i does not provide management frame security –Could effect routing, topology traffic etc. security –Should align with management frame security study group: Need to submit requirements to the group before November Only language changes needed to i –Do we need to do any other changes in i? Are there changes needed for allowing distributed authentication?

doc.: IEEE /1115r2 Submission J Chhabra, A. R. Prasad, J. Walker, H. AokiSlide Conclusion Security model builds on top of i –Minimal language changes Manageable key complexity –O(num_neighbors) Need to submit requirements to the management frame security group