Applied cryptography Project 2

1. Applied cryptographyProject 2

2. A demo Chat server registration Please enter a login name : > Alice Please enter the certificate file name: > c:\cert.cer Congratulations Alice! You have registered with the chat server <terminate program> Logging into the server Please enter login name: > Alice <challenge response> Welcome Alice! <Display contact list> CSE539 Applied Cryptography- 2005

3. A demo Alice Bob • Add Contact • Chat • Enter your choice: > 1 Enter contact name: Bob Bob has been successfully added to you contact list Alice has added you to her contact list • Add Contact • Chat • Enter your choice: > 2 Enter contact name: Bob Alice : Hi Bob Bob: Hello Alice: Hi Bob Bob: Hello CSE539 Applied Cryptography- 2005

4. Sensor Network Security Prepared by: Smitha Satish For CSE 539 ‘05

5. What is a sensor network? • Consists of spatially distributed sensors • Sensors work cooperatively • Used to monitor or detect phenomena at a particular location • Sensor node has sensing, data processing and communication components • Resource constrained, limited battery CSE539 Applied Cryptography- 2005

6. Applications of sensor networks • Environmental monitoring – great duck island • Video surveillance • Traffic monitoring • Air traffic control • Robotics • Cars • Home monitoring • Industrial and manufacturing automation. CSE539 Applied Cryptography- 2005

7. Sensors Communication link between sensors Control Node NodeNode Insecure Communication links Internet Base Station Security in sensor networks • Bio sensor networks with security requirements • Data confidentiality • Data authentication • Data availability • Data integrity • Data Freshness CSE539 Applied Cryptography- 2005

8. Sensor node characteristics • Vulnerability of nodes to physical capture • Lack of a-priori knowledge of post-deployment configuration • Lower battery • Limited memory resources • Limited bandwidth and transmission power • Impracticality of public key cryptosystems CSE539 Applied Cryptography- 2005

9. Attack model • Eavesdropping • Loss of privacy of sensed data • Denial of service • Sensor node compromise CSE539 Applied Cryptography- 2005

10. Aspects of sensor network security • Cryptography • Key management • Secure routing • Location aware routing • Secure data integration CSE539 Applied Cryptography- 2005

11. Key distribution - requirements • Secure node-to-node communication • Addition of legitimate nodes • Prevent unauthorized nodes • No prior knowledge of deployment • Low computational and storage requirement CSE539 Applied Cryptography- 2005

12. Single network wide key Use shared network wide key and bootstrap pair-wise keys and append a MAC Advantages: • Minimal storage requirements • No need for key exchange or discovery • Only symmetric encryption can be used • Resistant to DoS Disadvantages: • Single node compromise leads to network compromise CSE539 Applied Cryptography- 2005

13. Pre-deployed pair-wise key • Every node shares unique symmetric key with every other node Advantages: • Resilience to node capture • Compromised keys can be revoked • No need for key exchange or discovery • Only symmetric encryption can be used Disadvantages: • High storage requirements • No scalability CSE539 Applied Cryptography- 2005

14. The one with Trent • Sensor nodes authenticate to trusted base station which provides link key to the pair Advantages: • Resilience to node capture • Compromised keys can be revoked • Small memory requirement Disadvantages: • Base station is target for compromise • No scalability • You need protocols for key exchange or discovery CSE539 Applied Cryptography- 2005

15. Asymmetric cryptography • Use asymmetric keys to perform symmetric key exchange • Elliptic curve cryptography Advantages: • Resilience to node capture • Compromised keys can be revoked • Fully scalable Disadvantages: • Requires asymmetric key hardware • Denial of service • Node replication CSE539 Applied Cryptography- 2005