1. Key management in wireless sensor networks Kevin Wang

2. About WSN What is wireless sensor networks? –Definition Inexpensive, limited resources … –Constraints Limited power, computing ability, memory size and communication protocol –Application Military or hospital …

3. For example Berkeley-designed MICA2 –8 Mhz Atmel CPU –Instruction memory size is 128 kb –Data usage is 4 kb of RAM –Flash memory size is 512 kb –19.2 kbps application bandwidth up to a range of 10 – 20 meter –At full power the MICA2 will run for about two weeks before exhaustion and up to one year using sleep modes –Tiny OS

4. Security Risks in Wireless Sensory Networks Eavesdropping –Confidentiality Packet Injection –Access control –Integrity Jamming Replay Denial of Service Adversary K K K K

5. Problems Focus on –Key management –Clustering and Routing problem –Power consumption –Handoff problem Mobile node

6. Key management for WSN 1/4 Models –Hierarchical and Distributed WSN

7. Key management for WSN 2/4 Communication types –Unicast Nodes to headers Nodes to nodes Header to header –Multicast Header to nodes –Broadcast Server to nodes Server to headers

8. Key management for WSN 3/4 Key predistribution types –Deterministic –Probabilistic –Hybrid

9. Key management for WSN 4/4 Dynamic key generation algorithms for distributing –Pair-wise –Group-wise –Network-wise

12. Clustering problem Cluster problem –Random deployment Need an efficient algorithm to cluster –Use deployment knowledge Impracticable or infeasible: DDHV-D scheme

13. Routing problem –Shortest path is good? –Find dynamic paths to reach max-life of WSN –Solution: Static –GA, NN, … Mobile –Dynamic tiny GA …

14. Power consumption In WSN, the energy is an important dominated factor Deliver messages will consumption much energy –Deliver one bit : execute one instruction = 200~2900 : 1 But if fix the key function then the entire WSN will be weakness. So we consider power constraint and propose a novel scheme –Dynamic key-generation function –And the key function fulfill the power constraint

15. Handoff problem No move no handoff Mobile nodes –Headers verse nodes –In mobile WSN, as nodes moving, then the secure problem will be more important. ?

16. Question

17. Our scheme