Security in Wireless Sensor Networks - Adrian Perrig, John Stankovic, and David Wagner

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Security in Wireless Sensor Networks- Adrian
Perrig, John Stankovic, and David Wagner

• Presented by
• Soumyajit Manna
• Computer Science
• Kent State University.

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Outline

• Introduction
• A Secure System
• Network Security Service
• Conclusion

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Introduction

• Sensor
• - An Electronic device used to measure
  physical quantity, such as temperature, pressure,
  loudness and convert them into electronic signal
  of same kind.
• - A device that produces a measurable
  response to a change in a surrounding condition.
  

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Introduction Cont
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Introduction Cont.

• Current Application in Sensor Network
• - Freeway Traffic
• - Climate Control
• - Military Application
• - Pollution Control level
• - Monitor Ocean wildlife
• - Home environmental sensing systems for
  temperature, light, moisture, and
  motion

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Introduction Cont..

• Challenges in Sensor Network
• Energy, Memory, Computation and Communication
• Constraints.
• Deployment in accessible area. May cause physical
  attack.
• Level of dynamics, like obstacles, weathe,number
  of nodes, failures, captures are possible, so
  traditional mode of security cannot be applied in
  Sensor Network.
• Security Issues
• Key Establishment
• Secured Routing
• Authentication, Secrecy
• Privacy
• Robustness to DOS attack, Node Capture

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Outline

• Introduction
• A Secure System
• Network Security Service
• Conclusion

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Secure System

• Standalone security
• Separate module provides security to whole
  Network
• ? Flawed approach to network security
• Integrated security in every components
• Achieve a secure system
• Components designed without security can become a
  point of attack

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Key Establishment and Trust Setup

• Simple, secure, and efficient key-distribution
  for large scale sensor networks
• Key establishment solution
• Network-wide shared key
• Compromise of even a single node would reveal the
  secret key
• Single shared key to establish a set of link keys
• One per pair of communicating nodes
• Set up the session keys and erase the
  network-wide key
• Does not allow addition of new nodes after
  initial deployment

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Key Establishment and Trust Setup cont.

• Key establishment solution
• Public-key cryptography
• Diffie-Hellman key establishment
• A node can set up a secure key with any other
  node in the network
• Beyond the capabilities of sensor networks
• Shared unique symmetric key between each pair of
  nodes
• Doesnt scale well
• Each node needs to store n-1 keys, and n(n-1)/2
  keys in the network

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Key Establishment and Trust Setup Cont.

• Key establishment solution
• Bootstrapping keys
• Each node share only a single key with the
  trusted base station
• Set up keys with other nodes through the base
  station
• Random-key redistributions protocols
• Each sensor node chooses key ring from large key
  pool of symmetric keys
• If two nodes share a common key, they can
  establish a session key

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Key Establishment and Trust Setup Cont.

• Greater the key establishment probability is,
  more nodes can set up keys to obtain a fully
  connected network
• No central trusted base station

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Secrecy and Authentication

• Cryptography are of two type
• End to end Cryptography
• High level of security can be achieved
• Keys are to be set in all nodes in the network
• So for huge network this is quite impractical
• Link Layer Cryptography (hop-by-hop)
• Key is shared throughout the network (so with its
  next one)
• It is easy to implement.
• Due to shared key, it is easily to eavesdrop or
  alter message.
• Cryptography entail a performance cost for extra
  computation so there is tradeoff between security
  level and computational cost.

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Privacy

• Risk involve in Privacy
• Spying
• Deployment of secret surveillance network over
  unaware node.
• Function Creep
• Sensor networks initially deployed for legitimate
  purposes might subsequently be used in
  unanticipated and even illegal ways
• Privacy approach
• Data Encryption Access Control
• Query process in distributed manner

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Privacy Cont.

• Technology alone is unlikely to be able to solve
  the privacy problem
• A mix of societal norms, new laws, and
  technological responses are necessary

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Robustness to Communication DoS

• DoS attack
• Broadcasting a high energy signal
• In case of powerful transmission the entire
  system communication can be jammed.
• Violating the 802.11 MAC protocol
• By transmitting while a neighbor is also
  transmitting or by continuously requesting
  channel access with a RTS signal

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Solution

• Defense against jamming
• Spread-spectrum communication
• Not commercially available.
• Jamming-resistant network
• Detecting the jamming, mapping the affected
  region, then routing around the jammed area.
• Frequency hopping

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Jamming and Mapping Example
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Secure Routing

• Security goals for
• Integrity, Authenticity and message availability.
• Some of the attacks for routing are
• DoS attack
• Node Capturing
• Injecting attack
• Malicious information is been injected in the
  network
• Wormhole attack

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Wormhole Attack Example
http//www.wings.cs.sunysb.edu/ritesh/wormhole.ht
ml
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Resilience to Node Capture

• Node Capture attack is defined to be
• Capturing of node, extracting cryptographic
  information and then modifying the program
  according to the attackers need which
  ultimately comes under the control of attacker.
• This above phenomenon is due to the physical
  location of sensor network where the are placed.
• Challenges
• Building of resilient network
• Operate correctly even when several nodes have
  been compromised

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Resilience to Node Capture cont..

• Direction for resilient networks
• Detect inconsistencies
• Replicate state across the network and use
  majority voting
• E.g., sending packets along multiple, independent
  paths and checking at the destination for
  consistency
• Crosscheck multiple, redundant views of the
  environment
• Extreme outliers may indicate malicious spoofed
  data
• Defenses based on redundancy are good for sensor
  networks

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Detect Inconsistency Example
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Outline

• Introduction
• A Secure System
• Network Security Service
• Conclusion

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Network Security Service

• High-level network security services
• Secure group management
• In-network data aggregation and analysis
• Low computation and communication costs
• Intrusion detection
• Secure group ? decentralized intrusion detection
• Secure data aggregation
• Avoid overwhelming amounts of traffic back to the
  base station (sink)

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Secure Group Management

• Limitation in computing and communication
  capabilities
• Data aggregation and analysis can be performed by
  groups of nodes
• Secure protocol for group management
• Nodes comprising the group
• May change continuously and quickly
• Group computation and communication
• The outcome of the groups communication
  transmitted to a base station
• The outcome must be authenticated
• Any solution must be efficient in terms of time
  and energy

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Intrusion Detection

• Intrusion detection is expensive in terms of the
  networks memory, energy, and limited bandwidth
• Decentralized intrusion detection
• Secure group
• Decentralized intrusion detection
• Fully distributed and inexpensive in terms of
  communication, energy, and memory requirements

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Secure Data Aggregation

• Data aggregation
• Avoid overwhelming amounts of traffic back to the
  base station
• SIA
• The aggregator and a fraction of the sensor nodes
  may be corrupted
• Randomly sampling a small fraction of nodes
• Checking that they have behaved properly
• The answer given by the aggregator is a good
  approximation of the true value

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Conclusion

• Security in wireless sensor network is more
  challenging than in the conventional networks
• Sever constraints and demanding deployment
  environments of wireless sensor networks
• We have the opportunity to architect security
  solutions from the outset