Security Issues In Sensor Networks

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Security Issues In Sensor Networks

• By
• Priya Palanivelu

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What Is A Sensor Network?

• A network is formed when a set of small sensor
  devices that are deployed in an ad hoc fashion
  cooperate for sensing a physical phenomenon.

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Typical application of sensor networks

• Military sensor networks to detect enemy
  movements, the presence of hazardous material
  (such as poison gases or radiation, explosions,
  etc.)
• Environmental sensor networks (such as in plains
  or deserts or on mountains or ocean surfaces) to
  detect and monitor environmental changes.
• Wireless traffic sensor networks to monitor
  vehicle traffic on a highway or in a congested
  part of a city.
• Wireless surveillance sensor networks for
  providing security in a shopping mall, parking
  garage, or other facility.

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Communication Architecture

• The sensor nodes communicate using RF
• The sensor nodes establish a routing forest, with
  a base station at the root of every tree
• Periodic transmission of beacons allows nodes to
  create a routing topology.
• The base station accesses individual nodes using
  source routing.

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Challenges Of Sensor Network

• Energy consumption primarily
• By radio communication
• Need to minimize communication overhead
• Reliance on asymmetric digital signature
• Long signatures with high communication overhead
  of 50-1000 bytes per packet
• Very high overhead to create verify signature
• Symmetric broadcast authentication is impractical

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Requirements for sensor networks security

• Data Confidentiality
• From the observed communication pattern set up
  secure channels between nodes and base stations
• Data Authentication
• Construct authenticated broadcast from symmetric
  primitives only
• Introduce asymmetry with delayed key disclosure
  and one way function key chains
• Data Integrity
• Data Freshness
• Recent data
• No replay of data

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Communication Pattern Of The Sensor Network

• 1) Node to base station communication, e.g.
  sensor readings.
• 2) Base station to node communication, e.g.
  specific requests.
• 3) Base station to all nodes, e.g. routing
  beacons, queries or reprogramming of the entire
  network.

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SPINS Security Protocols for Sensor Networks
security building blocks optimized for source
constrained environments and wireless
communication.
SPINS
_TESLA
SNEP
Timed, Efficient, Streaming, Loss-tolerant
Authentication Protocol),
Secure Network Encryption Protocol
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Important Baseline Security Primitives

• SNEP ? Data confidentiality, two-party data
  authentication, and data freshness
• µTESLA ? new protocol which provides
  authenticated broadcast for severely
  resource-constrained environments.

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SNEP Data Confidentiality, Authentication,
Integrity, and Freshness

• Low communication overhead
• Adds only 8 bytes per message
• Uses counter
• Counter value is kept at both end points
• Provides semantic security
• Prevents eavesdroppers from interfering the
  message content from the encrypted message
• Data authentication, replay protection, and
  weak/strong message freshness

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SNEP-mechanism

• Communicating parties share a counter, which is
  used as an Initialization Vector (IV)
• Counter is not sent with the message
• Block ciphers are in Counter Mode (CTR)
• Counter incremented after each block
• MAC used to achieve 2 party data authentication
  and data integrity
• Counter value is never repeated
• Counter value in MAC prevents replay attacks

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TESLA vs. µTESLA

• TESLA
• Authenticates initial packet with a digital
  signature
• Too expensive for sensor nodes
• Disclosing a key in each packet requires too much
  energy(24bytes/packet)
• Expensive to store one-way key chain
• µTESLA
• Uses symmetric mechanism
• Discloses key once every epoch
• Restricts number of authenticated senders

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µTESLA Overview

• Base station (BS) broadcasts authenticated
  information to nodes
• BS and nodes are loosely time synchronized
• Each node knows the upper bound on max.
  synchronization error
• BS computes a MAC on the packet
• The key is secret at this point
• Sensor receives the packet stores it in buffer
• BS broadcasts the verification key to all
  receivers
• Node verifies the authenticity of the key
• Node uses key to authenticate the packet in the
  buffer

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Thank you!!!