Wireless Sensor Network Security

1
Wireless Sensor Network Security

• Anuj Nagar
• CS 590

2
Introduction

• Typical Wireless Sensor Network (WSN)

3
Need for security

• WSNs are becoming a cost effective, practical way
  to go about deploying sensor networks.
• Large range of applications from civilian to
  military purposes.
• Pose different challenges as compared to
  traditional networks. Hence different mechanisms
  must be brought about.
• Enormous research potential.

4
Main Aspects

• Obstacles to WSN security.
• Requirements of a Secure WSN.
• Attacks.
• Defensive Measures.

5
Obstacles to WSN Security

• Very limited resources
• Limited memory and Storage space A typical
  sensor has a 16 bit 8 Mhz CPU with 10K RAM, 48K
  Program Memory and 1M flash storage.
• Power limitation

6
Obstacles to WSN Security -continued

• Unreliable Communication
• Unreliable Transfer Packet-based routing of
  the sensor network is connectionless hence
  unreliable.
• Conflicts Even if the channel is reliable, the
  communication may still be unreliable due to
  broadcast nature of WSN.
• Latency Multi-hop routing, network congestion
  and node processing can lead to greater latency
  in the network.

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Obstacles to WSN Security continued..again

• Unattended Operation
• Exposure to Physical Attacks.
• Managed Remotely Hard to detect physical
  tampering.
• No Central Management Point Ideally a WSN
  should have no central management point. However,
  if the network is designed incorrectly it may
  lead to greater congestion.

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Security Requirements

• Shares some common points with traditional
  networks but also presents unique problems of its
  own.
• Data confidentiality Most important issue
  in any network.
• Data integrity Inability to modify data.
• Data freshness Ensures that no old messages have
  been replayed. Essential for shared key schemes.

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Security Requirements - continued

• Availability Adjusting existing encryption
  algorithms to fit within a WSN has costs
• Additional computation consumes more energy.
• Additional communication consumes more energy.
• Threat of a single point failure if a central
  management point scheme is used.

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Security Requirements continued..again

• Self Organization A WSN is typically an ad hoc
  network which requires every node to be self
  organizing and self healing.
• Time Synchronization e.g. to calculate the end
  to end delay time of packets between nodes.
• Secure localization Ability to accurately and
  automatically locate each sensor in the network.
• Authentication

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Attacks

• Vulnerable to a multitude of attacks such as
  DoS, traffic analysis, privacy violation,
  physical attacks and so on.
• DoS Jamming a node or set of nodes by
  transmission of a radio signal that interferes
  with radio frequencies being used.
• Violate the communication protocol thus
  depleting valuable battery life.

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More attacks

• Sybil attack
• Defined as a malicious device illegitimately
  taking on multiple identities.
• Originally used against peer to peer networks but
  may also be used to disrupt routing algorithms,
  data aggregation etc.
• Traffic Analysis Attacks Take over the base
  station/nodes closest to base station.

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Yet more attacks

• Node replication attacks.
• Attacks against privacy.
• Physical attacks.

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Defensive Measures

• Key Establishment.
• Secure Broadcasting and Multicasting.
• More efficient routing protocols.
• Intrusion Detection.

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Conclusion

• Emerging field in a traditional world of computer
  security.
• A vast amount of research work is being conducted
  in this area.
• Possible thesis ideas Working on key
  distribution schemes, modifying existing
  encryption algorithms, working on the IDS side of
  things.

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References

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