Hierarchical Self-healing Key Distribution for Heterogeneous Wireless Sensor Networks

1. Hierarchical Self-healing Key Distribution forHeterogeneous 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. Homogeneous WSNs • 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

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 = [rk1, rk2] mKi = [mk1, mk2] =[h(Gi,rk1), h(Gi,rk2)] gKi = …

14. Key Generation reverse hash chain foward hash chain gKi[j] = kR[m-j+1]+kF[j] kR[j] = hRj(mk1) = hR(hR(hR(…hR(mk1)))) kF[j] = hFj(mk2) = hF(hF(hF(…hF(mk2))))

15. Key Distribution • mk2 is given to each sensor as seed sF for the forward hash chain • At the start of each session, the group manager generates kR[m-j+1] using mk1 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. Conclusion • 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!