1. Privacy and Security in Embedded Sensor Networks Daniel Turner 11/18/08 CSE237a

2. The Problem Capture Attacks Wireless Communication Limited Power  Resource drain attack  Extra message length costly Limited Resources  CPU: No asymmetric crypto  RAM / Flash: minimal state

3. Confidentiality (Encryption)‏ Block Cipher: DES, Skipjack, AES,... Init Vector:  Additional Randomness TinySec: CBC (10% pwr increase)‏  IV = 4 Bytes MiniSec: OCB (8.3% pwr increase)‏  No text expansion

4. Authenticity (MAC)‏ MAC: cryptographic secure checksum TinySec:  Replace CRC with MAC (3% pwr increase)‏ MiniSec:  Instead of an IV OCB produces a MAC

5. Additional Areas Secure Routing  Prevent Black holes Replay Attacks  Counters and Bloom filters Keying  Global key  Pair wise keys  Something between

6. Future Work Better Keying Methods Optimized Ciphers Break implicit assumptions about loose synch between nodes

7. Questions?

8. Key Management Bad: All pairs or Single key LEAP Keys  Base-station  Pair: Computed at boot from K_in  Cluster: pairwise sending of cluster key  Global re-keying: Controller revokes node, sends new key

9. Replay Attacks TinySec: No protection MiniSec:  Counters in unicast (3 bit overhead)‏  Bloom filter in broadcast

10. Secure Routing Create a routing table using signed IDs  Challenges: prevent liars  No node duplication: prevent Sybil

11. Secure Routing

12. Create a routing table using signed IDs  Challenges: prevent liars  No node duplication: prevent Sybil Route via Multi-path forwarding  3 paths per group  (Random) direction string Honeybee to eliminate bad nodes