1. A Study on Certificate Revocation in Mobile Ad Hoc Networks Wei Liu,Hiroki Nishiyama,Nirwan Ansari & Nei Kato ICC 2011 Nadia Adem 10/27/2014

2. Attacks in MANEN Self-organized Wireless Dynamic Security attacks Certificates Isolation Promptly Accurately Revoked Accused

3. Outline Some MANETS security schemes Clustering-based scheme Scheme main idea The way it works Issues Performance Analysis Contributions Weak aspects Summary

4. MANET Security Schemes Certificate control approach-CA Digital certificate expires Valid certificate nodes- certificates revoked Voting-based scheme- NO CA Nodes vote - variable weight Ticket revoked Suicide-based approach- NO CA Node sacrifice itself

5. Clustering-based Scheme False Accusation Malicious Attack Overhead communications Time

6. How does it work? CA CM2 node normal attacker warned CH CM1 CM2 CH CM1 CM2 CM1 ADP CRP CM2 CH CM1 CM3 detect false accusations Quick revocation/recovery Small overhead Resolve false accusation/recovery

7. Issues and Solutions accuser Accuser nodes Warned Recovery requester Can not accuse

8. Node Release Method Threshold approach Accuser in warning list till K nodes or more accuse the accused node Accuser MISBEHAVING LEGITIMATE

9. Performance Evaluation Simulation Parameters ParameterValue Number of nodes 50 normal nodes and 10 - 60 malicious nodes Mobility modelRandom-Waypoint Node placementRandom Routing protocolAODV Pause time5 sec Transmission range250 m Terrain dimensions1 km 2

10. Performance Evaluation

11. Node release threshold sch. Applied Not applied

12. Performance Evaluation False accusations Threshold Detection time

13. Contributions Quickly revoke certificates of accused nodes Distinguish false accusation Restore a node’s accusation ability

14. Weak Aspects Existence of CA Threshold determination Malicious nodes communicate with all other nodes in the cluster!

15. Summary Security Scheme for MANETs Certificate revocation scheme Advantages Performance shortcoming