Applied cryptography Project 2

2CSE539 Applied Cryptography 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 Logging into the server Please enter login name: > Alice Welcome Alice!

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

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

5CSE539 Applied Cryptography 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

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

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

8CSE539 Applied Cryptography 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

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

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

11CSE539 Applied Cryptography 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

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

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

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

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