Security in Wireless Sensor Networks

1
SecurityinWireless Sensor Networks

• by
• Toni Farley

2
Security Concerns

• Security Concerns Defined
• Integrity - Ensure that information is accurate,
  complete, and has not been altered in any way.
• Availability - Ensure that a system can
  accurately perform its intended purpose and is
  accessible to those who are authorized to use it.
• Confidentiality - Ensure that information is only
  disclosed to those who are authorized to see it.

Integrity
Availability
Confidentiality
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Security Concerns

• Authentication Ensure correctness of claimed
  identity.
• Authorization Ensure permissions granted for
  actions performed by entity.

Authentication
Authorization
ICA3
4
Points of Security Concern

• System
• System Integrity
• Availability
• Source
• Authentication
• Authorization
• Data
• Data Integrity
• Confidentiality

WSN
Data
Source
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Threats

• Authentication
• Man in the middle
• Data Integrity
• Modification
• Forgery
• Deletion
• Replay
• Confidentiality
• Eavesdropping

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Wireless Security

• Magnified Threats
• Detectability Ability to discover a wireless
  system
• Theft of Service Unauthorized use of wireless
  signal
• Interception Easy to capture signals
  transmitted through air
• Limited Resources
• Low b/w
• Low memory capacity
• Slow CPU
• Battery Power Limits

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Current Solution Encryption

• Symmetric (private key) encryption
• Fixed keys cannot be changed when compromised
• Dynamic keys require high cost key exchange
  protocol
• Faster algorithms computational overhead
• Asymmetric (public/private) key encryption
• Data sent to many devices must be encrypted
  separately with each devices public key
• Longer keys provide better security
• Longer keys require more resources, which becomes
  problematic if many keys are needed

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Current Solution Encryption

• Pretty Good Privacy (PGP)
• Uses session key to encrypt data, thus only need
  to encrypt data one time for multiple recipients
• Uses public keys to encrypt session key, requires
  multiple smaller encryptions
• Overhead is reduced, but still exists

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Research SPINS

• Security Protocols for Sensor Networks 1
• Securing Node/Base Station communications
• Secure Network Encryption Protocol (SNEP)
• Secure channels for confidentiality
• Data integrity through authentication
• Data freshness through partial message ordering
  (weak) and total order with delay estimation
  (strong)
• micro Timed, Efficient, Streaming, Loss-tolerant
  Authentication Protocol (µTESLA)
• Authentication through asymmetric authenticated
  broadcast

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Research Security for Sensor Networks

• Security for Sensor Networks 2
• Securing Node/Base Station communications
• Broadcasts of end-to-end encrypted packets
• Authentication
• Integrity
• Confidentiality
• Replay
• Base station looks for corrupted packets or long
  period of inactivity
• Mechanism for detecting bad behavior

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Research Secure Routing in WSN

• Security Routing in Wireless Sensor Networks
  Attacks and Countermeasures 3
• Describes routing attacks
• Known attacks
• Invented attacks
• Protocol specific attacks
• Describes countermeasures for each attack
• Encryption with globally shared key
• Unique key between each node base station
• Neighbor authentication between nodes
• Authenticated broadcast techniques

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Security Sources

• SANS Glossary of Terms Used in Security and
  Intrusion Detection, http//www.sans.org/resources
  /glossary.phpC, May 2003.
• MobileBook
• Andrew S. Tanenbaum, Computer Networks, Prentice
  Hall, 2003.
• Encyclopedia of Cryptography and Security,
  Kluwer, to be published in 2004.

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Research References

• 1 SPINS Security Protocols for Sensor
  Networks. A. Perrig, R. Szewczyk, V. Wen, D.
  Culler, and J. Tygar. In Seventh Annual ACM
  International Conference on Mobile Computing and
  Networks (Mobicom), 2001.
• 2 Jeffery Undercoffer, Sasikanth Avancha,
  Anupam Joshi, and John Pinkston, Security for
  Sensor Networks 2002 CADIP Research Symposium
• 3 Secure Routing in Sensor Networks Attacks
  and Countermeasures, Chris Karlof and David
  Wagner, To appear in Elsevier's AdHoc Networks
  Journal, Special Issue on Sensor Network
  Applications and Protocols.