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 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 Results Conclusions Our Proposal Introduction Security in WSN 3/19

4. Security aspects 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 Results Conclusions Our Proposal Introduction Security in WSN 4/19

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

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

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

8. The Context Monitoring Algorithm  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 Results Conclusions Our Proposal Introduction Security in WSN 8/19

9. Functionalities of the CMA  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 Results Conclusions Our Proposal Introduction Security in WSN 9/19

10. Functionalities of the CMA  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. Results Conclusions Our Proposal Introduction Security in WSN 10/19

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

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

13. Results 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) Results Conclusions Our Proposal Introduction Security in WSN 13/19

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

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

16. Performances of the System 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 Results Conclusions Our Proposal Introduction Security in WSN 16/19

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

18. Conclusions 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 Results Conclusions Our Proposal Introduction Security in WSN 18/19

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