1. Security and Sensor Networks By Andrew Malone and Bryan Absher

2. Outline What are sensor networks? Applications Security Key Pre-distribution Key Capture Route Capture

3. Sensor Networks Sensor Network Collection of inexpensive sensors Wireless communication Randomly distributed nodes Sensor (node) Ultra low power ~10 kilobytes of storage ~10MHz clock 100 m – 900 m communication range (RF)

4. Benefits of Ad-Hoc Sensor Networks Power Distance 2 Ad-Hoc Sensors Approach Linear Behavior

5. Applications Military Tracking troops Monitoring battlefields Scientific Collecting data Industrial Tracking packages Monitoring systems

6. Security Key Management Key Pre-Distribution Create a key pool Pre-Load nodes with keys Nodes share a connection if they share a key

7. Impractical Approaches to Key Distribution Single Mission Key One Key for Entire Network Assign unique keys to every node Excessive Memory Requirements

8. Adversary Model Cannot efficiently do cryptanalysis on communications Can physically capture data Can extract keys from nodes

9. More Efficient Key Distribution Create a key pool Preload nodes with a key ring Very small amount of storage Maintain high amount of security Increases payoff if a node is compromised

10. q-Composite Key Distribution Nodes are linked if they have q keys in common Decreases probability of connectedness Decreases initial payout for adversary

11. Comparison

12. Multi-link Reinforcement Use network topology to strengthen links A new key, K`, is computed using random numbers Random numbers sent across other links

13. Attacks on Sensor Networks Assume cryptanalysis of traffic hard Physically capturing nodes Capture Strategies Random Capture Key Capture Route Capture

14. Key Capture Compute the value of each node Value is the number of keys not already captured Capture the highest value node

15. Route Capture GNAVE algorithm Value each node by the amount of traffic

16. Comparison