Adaptive Security for Wireless Sensor Networks

1. Adaptive Security for Wireless Sensor Networks Master Thesis – June 2006

2. Table of contents I Introduction II Security Aspects in WSN III The Proposal - Security Manager - Context Monitoring Algorithm - Adaptive Security System Building Blocks - Building Blocks & Information procedure diagram IV Results V Conclusions 2/19

3. Introduction Introduction • Sensor nodes are able to improve lots of applications (medical, industrial, intelligent environments…) • Work is focused on the adaptive security of a wireless sensor networks • A new feature is introduced: the Security Manager • One specific scenarios has been studied: healthcare monitoring Security in WSN Our Proposal Results Conclusions 3/19

4. Security aspects Introduction • Weak points of Security in WSN: • Communication between sensor nodes and the aggregator. • The aptitude of a network to counterattack. • The ability to protect privacy • Real need for a secure and an easy-to-use network • We assume that the base station is a point-of-trust • The nodes must have robust solution against attacks: • Use of authentication protocols and cryptography techniques Security in WSN Our Proposal Results Conclusions 4/19

5. Our Proposal Introduction • Security Manager • Context Monitoring Algorithm • Adaptive Security System building blocks • Building blocks and information procedure diagram Security in WSN Our Proposal Results Conclusions 5/19

6. Authentication : • Diffie-Hellman • Elliptical curve equation Encryption : • RC5 algorithm • X-OR operation Flags Key determination protocol Message Encryption protocol Authentication and Encryption Processes Introduction Security in WSN Our Proposal Results Conclusions 6/19

7. Key length (in bytes) Number of rounds Block length of clear text Security Levels Introduction Three Levels of Security: • Low Level RC5 - 32/6/3 • Medium Level RC5 - 32/6/5 • High Level RC5 - 32/12/5 Security in WSN Our Proposal Results Conclusions 7/19

8. The Context Monitoring Algorithm Introduction • Determine an adaptive reaction to maintain the network’s integrity and functionalities. • Responsible for: • Tracking and Reporting the network’s status • Checking the anomalies • Monitoring the context information Security in WSN Our Proposal Results Conclusions 8/19

9. Functionalities of the CMA Introduction • Broadcast requests • Analize traffic: Check the number of messages. Below expected  Find deficient node Increase the level of security Above expected  Revoke and change the nodes’ key Increase the level of security Security in WSN Our Proposal Results Conclusions 9/19

10. Functionalities of the CMA Introduction • Scan for attacks: • CRC Errors  Change Channel • Aggregator DoS  Revoke and change all the keys Increase the level of security • Compromised node  Revoke its key Send notification to the user and to the hospital database • Power Control Management • Check the batteries status and send notification to the user • Control the emitting power of nodes and aggregator. Security in WSN Our Proposal Results Conclusions 10/19

11. Adaptive Security System Building Blocks Introduction Security in WSN Our Proposal Results Conclusions 11/19 (half-time)

12. Building Blocks & Information procedure diagram Introduction Security in WSN Our Proposal Results Conclusions 12/19

13. Results Introduction • Aim : Find the best compromise between performance and security • Conditions: • Test bed: - Processor Frequency: 540MHz - Processing Unit: 32 bits • Real case (Mica2dot): - Processor Frequency: 4Mhz - Processing Unit: 8 bits • Assumptions: • Linear relation between the 2 processing units • The gain in processing time is equivalent to the gain of battery lifetime • Reference – High Level of Security • Key Exchange frequency : 4hours • Message Sample Rate : 10 sec (according to Code Blue) Security in WSN Our Proposal Results Conclusions 13/19

14. Performances of the System Introduction • Evolution of the processing time and the key robustness regarding the level of security Security in WSN Our Proposal Results Conclusions 14/19

15. Performances of the System Introduction • Using our simulator and creating a typicalday scenario, we have obtained the following results: Security in WSN Our Proposal Results Conclusions 15/19

16. Performances of the System Introduction • Why did we choose 4hours for the key exchange frequency? • Only in the trusted place the time to break the key is less than 4 h. • By increasing the key exchange frequency the battery consuming highly increases Security in WSN Our Proposal Results Conclusions 16/19

17. Performances of the System Introduction • The influence of the message sample rate on the energy consumption Security in WSN Our Proposal Results Conclusions 17/19 (almost done)

18. Conclusions Introduction • New solution based on the ECC and the Diffie-Hellman protocol • Caution when labeling a place as “trusted” • The adaptability of the system increases sensor nodes battery’s lifetime • The user’s behavior is intimately connected to the security parameters, i.e. to the battery lifetime saved. • Ability to track the network status and ensure a quick response Security in WSN Our Proposal Results Conclusions 18/19

19. Thank you for your attention … and Happy New Year 