Paper Presentation By : Gaurav Dixit (gdixit@vt.edu)

1. Adaptive Network Management for Countering Selective Capture in Wireless Sensor Networks • Authors: Hamid Al-Hamadi and Ing-Ray Chen Paper Presentation By : Gaurav Dixit (gdixit@vt.edu)

2. Critical node (selective) capture near base station The Problem

3. The Problem

4. The Problem

5. The Problem No access to base station

6. Dynamic radio adjustment • Multisource multipath • Voting-based intrusion detection The Solution Proposed

7. Dynamic radio adjustment

8. Dynamic radio adjustment

9. Dynamic radio adjustment • SNs increases radio range dynamically to connect to n0 1-hop neighbors

10. Multisource multipath Event Occurred

11. Multisource multipath Event Occurred

12. It would consume more energy • It would be more robust • What is best redundancy level? Multisource multipath

13. Evict compromised nodes • “host IDS” run on SN to conserve energy • Each node monitors neighbors only. • False positives, false negatives. Voting-based intrusion detection

14. ms - source redundancy • mp - path redundancy • m – number of voters • TIDS – the intrusion detection interval Design parameters

15. Output: MTTF • Maximize MTTF by tuning design parameters. • Rq (tQ,j ) – probability of successful response to query j

16. Max queries, Nq before system dies • First term says system fails on query i+1 Output…

17. (if capture time is exponentially distributed) increasing bad nodes..

18. number of good and bad nodes number of forwarding neighbors (f =1/4, geographical routing) is

19. more than half of voting nodes bad (Voting) false positives.. selecting m neighbor nodes Good nodes give bad decisions due to host false positive probability

20. Re-adjusting good/bad node densities Thus, possibility of a bad at dist x from BS is

21. The Success Probability This is success probability of a path from SNj to BS.

22. Failure probability with multipath : Failure probability Failure probability with multiple source and multipath :

23. ‘Black ring’ consumes more energy • Multipath, multisource , frequent IDS consumes energy Energy!

24. No. of IDS cycle before SN energy exhaustion Energy! Transmit nb bits : Receive nb bits : Energy consumed by SN at x for processing ith query:

25. Number of SNs within range of SNs at distance x : Energy! Energy spent by a SN located at x in i-th IDS cycle.

26. On TD timer event: • BS determines design parameters, and notifies SNs of new TIDSand m. • SNs update new settings. Adaptive network

27. -- once in 4 weeks --once in 12 hrs to 3 days n0 = 7 Performance Optimal (mp ,ms ) values to counter ‘selective capturing’ (m=3):

28. High detection in High Attack strength

29. Low detection in High Attack strength

30. Effect of varying TIDS

31. MTTF comparison with Attack strength

32. Density of Good SNs at distance X vs. Time

33. MTTF comparison with Attack strength

34. Three ways studied to counter selective capture of sensor nodes. • Proved experimentally that there exist an optimum value for multiple paths and multiple sources. • Studied the trade-off between energy expense and robustness of WSN, thus extending usable lifetime of WSN. Conclusion

35. Thank you!