Privacy and Security in Embedded Sensor Networks Daniel Turner 11/18/08 CSE237a
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
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
Authenticity (MAC) MAC: cryptographic secure checksum TinySec: Replace CRC with MAC (3% pwr increase) MiniSec: Instead of an IV OCB produces a MAC
Additional Areas Secure Routing Prevent Black holes Replay Attacks Counters and Bloom filters Keying Global key Pair wise keys Something between
Future Work Better Keying Methods Optimized Ciphers Break implicit assumptions about loose synch between nodes
Questions?
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
Replay Attacks TinySec: No protection MiniSec: Counters in unicast (3 bit overhead) Bloom filter in broadcast
Secure Routing Create a routing table using signed IDs Challenges: prevent liars No node duplication: prevent Sybil
Secure Routing
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