1. Hierarchical Self-healing Key Distribution for Heterogeneous Wireless Sensor Networks Y.J. Yang, J.Y. Zhou, R.H. Deng, F. Bao Presenter: Jianying Zhou

2. Content Introduction Heterogeneous WSN Architecture Hierarchical Self-healing group Key Distribution Scheme Conclusion

3. Introduction Heterogeneous WSN Architecture Hierarchical Self-healing group Key Distribution Scheme Conclusion

4. Wireless Sensor Networks Wireless Sensor Networks (WSNs)

5. Self-healing Group Key Distribution Key Distirubtion & Management is Fundamental to Other Security Issues –Pairwise key distribution –Group key distribution Self-healing group key distribution especially suits WSNs’ lossy channel.

6. All Existing Work Consider Homogeneous WSNs Homogeneous WSN –All sensor nodes have the same capability –Homegeneous WSNs have scalability problem. Theoretical and empirical studies have corroborate this Homogeneous WSNs

7. Hierarchical Self-healing Key Distribution Motivated to Study Self-healing Group Key Distribution for Heterogeneous WSNs Hierarchical Self-healing Group Key Distribution –Adapting to the heterogeneous WSN architecture

8. Introduction Heterogeneous WSN Architecture Hierarchical Self-healing group Key Distribution Scheme Conclusion

9. Heterogeneous WSNs Heterogeneous WSNs Are A Better Alternative to Homogeneous ones –The network is partitioned into clusters, and each cluster is placed a cluster head –Cluster heads have better capability than sensor nodes –A cluster head acts an intermediary between sensor nodes and the base station

10. Heterogeneous WSNs

11. Introduction Heterogeneous WSN Architecture Hierarchical Self-healing group Key Distribution Scheme Conclusion

12. Key Hierarchy

13. Key Generation rK = [rk 1, rk 2 ] mK i = [mk 1, mk 2 ] =[h(G i,rk 1 ), h(G i,rk 2 )] gK i = …

14. Key Generation gK i [j] = k R [m-j+1]+k F [j] k R [j] = h R j (mk 1 ) = h R (h R (h R (…h R (mk 1 )))) k F [j] = h F j (mk 2 ) = h F (h F (h F (…h F (mk 2 )))) reverse hash chain foward hash chain

15. Key Distribution mk 2 is given to each sensor as seed s F for the forward hash chain At the start of each session, the group manager generates k R [m-j+1] using mk 1 as seed for the reverse hash chain, and broadcasts to sensors within its group –The broadcast scheme is essentially the Dutta et al.’s scheme, with a slight modification to rectify its weakness

16. Key Distribution The reverse hash chain is used to achieve self-healing property The forward hash chain is used to forward secrecy, i.e., sensors joined later cannot compute group keys of earlier sessions

17. Introduction Heterogeneous WSN Architecture Hierarchical Self-healing group Key Distribution Scheme Conclusion

18. Heterogeneous WSNs Have Better Scalability and Performance, As the Introduction of Powerful Group Managers Provides Shortcut for Data Transmission from Sensors to Base Station We Proposed Hierarchical Self-healing Group Key Distribution Tailored to Heterogeneous WSNs For This Scheme, We Assume Group Managers are Trusted. In the Original Submission, We Have a Scheme Handling Untrusted Group Managers

19. Thank You!