1. Wireless Sensor Network Security Anuj Nagar CS 590

2. Introduction Typical Wireless Sensor Network (WSN)

3. Need for security WSNs are becoming a cost effective, practical way to go about deploying sensor networks. Large range of applications from civilian to military purposes. Pose different challenges as compared to traditional networks. Hence different mechanisms must be brought about. Enormous research potential.

4. Main Aspects Obstacles to WSN security. Requirements of a Secure WSN. Attacks. Defensive Measures.

5. Obstacles to WSN Security Very limited resources: – Limited memory and Storage space : A typical sensor has a 16 bit 8 Mhz CPU with 10K RAM, 48K Program Memory and 1M flash storage. – Power limitation

6. Obstacles to WSN Security - continued Unreliable Communication : – Unreliable Transfer : Packet-based routing of the sensor network is connectionless hence unreliable. – Conflicts: Even if the channel is reliable, the communication may still be unreliable due to broadcast nature of WSN. – Latency: Multi-hop routing, network congestion and node processing can lead to greater latency in the network.

7. Obstacles to WSN Security – continued..again Unattended Operation: – Exposure to Physical Attacks. – Managed Remotely: Hard to detect physical tampering. – No Central Management Point: Ideally a WSN should have no central management point. However, if the network is designed incorrectly it may lead to greater congestion.

8. Security Requirements Shares some common points with traditional networks but also presents unique problems of its own. Data confidentiality: Most important issue in any network. Data integrity: Inability to modify data. Data freshness: Ensures that no old messages have been replayed. Essential for shared key schemes.

9. Security Requirements - continued Availability: Adjusting existing encryption algorithms to fit within a WSN has costs : – Additional computation consumes more energy. – Additional communication consumes more energy. – Threat of a single point failure if a central management point scheme is used.

10. Security Requirements – continued..again Self Organization: A WSN is typically an ad hoc network which requires every node to be self organizing and self healing. Time Synchronization: e.g. to calculate the end to end delay time of packets between nodes. Secure localization: Ability to accurately and automatically locate each sensor in the network. Authentication

11. Attacks Vulnerable to a multitude of attacks such as DoS, traffic analysis, privacy violation, physical attacks and so on. DoS: Jamming a node or set of nodes by transmission of a radio signal that interferes with radio frequencies being used. Violate the communication protocol thus depleting valuable battery life.

12. More attacks Sybil attack: –Defined as a “malicious device illegitimately taking on multiple identities.” –Originally used against peer to peer networks but may also be used to disrupt routing algorithms, data aggregation etc. Traffic Analysis Attacks: Take over the base station/nodes closest to base station.

13. Yet more attacks Node replication attacks. Attacks against privacy. Physical attacks.

14. Defensive Measures Key Establishment. Secure Broadcasting and Multicasting. More efficient routing protocols. Intrusion Detection.

15. Conclusion Emerging field in a traditional world of computer security. A vast amount of research work is being conducted in this area. Possible thesis ideas: Working on key distribution schemes, modifying existing encryption algorithms, working on the IDS side of things.

16. References [1] I. F. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci. A survey on sensor networks. IEEE Communications Magazine, 40(8):102–114, August 2002. [2] P. Albers and O. Camp. Security in ad hoc networks: A general intrusion detection architecture enhancing trust based approaches. In First International Workshop on Wireless Information Systems, 4th International Conference on Enterprise Information Systems, 2002. [3] R. Anderson and M. Kuhn. Tamper resistance - a cautionary note. In The Second USENIX Workshop on Electronic Commerce Proceedings, Oakland, California, 1996. [4] R. Anderson and M. Kuhn. Low cost attacks on tamper resistant devices. In IWSP: International Workshop on Security Protocols, LNCS, 1997. [5] T. Aura, P. Nikander, and J. Leiwo. Dos-resistant authentication with client puzzles. In Revised Papers from the 8th International Workshop on Security Protocols, pages 170–177. Springer-Verlag, 2001.