Applied cryptography Project 2 A demo Chat server

1
Applied cryptographyProject 2
2
A demo

• Chat server registration
• Please enter a login name
• gt Alice
• Please enter the certificate file name
• gt c\cert.cer
• Congratulations Alice! You have registered with
  the chat server
• ltterminate programgt
• Logging into the server
• Please enter login name
• gt Alice
• ltchallenge responsegt
• Welcome Alice!
• ltDisplay contact listgt

3
A demo

Alice
Bob

• Add Contact
• Chat
• Enter your choice

gt 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

gt 2 Enter contact name Bob Alice Hi Bob Bob
Hello
Alice Hi Bob Bob Hello
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

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.

7
Security in sensor networks

• Bio sensor networks with security requirements
• Data confidentiality
• Data authentication
• Data availability
• Data integrity
• Data Freshness

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

9
Attack model

• Eavesdropping
• Loss of privacy of sensed data
• Denial of service
• Sensor node compromise

10
Aspects of sensor network security

• Cryptography
• Key management
• Secure routing
• Location aware routing
• Secure data integration

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

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

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

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

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