SECURITY PROTOCOLS FOR WIRELESS SENSOR NETWORK

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SECURITY PROTOCOLS FOR WIRELESS SENSOR NETWORK

• 
  Presented by
• 
  Chetan Rana
• U08CO213

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INTODUCTION

• Wireless Sensor Networks are networks that
  consists of sensors which are distributed in an
  ad hoc manner.
• These sensors work with each other to sense some
  physical phenomenon and then the information
  gathered is processed to get relevant results.
• Wireless sensor networks consists of protocols
  and algorithms with self-organizing capabilities.

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Refhttp//esd.sci.univr.it/images/wsn-example.png

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WSN ARCHITECHTURE

• Sensor motes (Field devices) capable of routing
  packets on behalf of other devices.
• Gateway or Access points A Gateway enables
  communication between Host application and field
  devices.
• Network manager A Network Manager is
  responsible for configuration of the network,
  scheduling communication between devices (i.e.,
  configuring super frames), management of the
  routing tables and monitoring and reporting the
  health of the network.
• Security manager The Security Manager is
  responsible for the generation, storage, and
  Management of keys.

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WSN ARCHITECTURE
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WSN Topologies

• Wireless Links Numerous paths to Connect to the
  same destination
• Topology
• - Star
• - Mesh
• - Hybrid

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Star Topology

• Single Hop to Gateway
• Gateway serves to communicate between nodes
• Nodes cannot send data to each other directly

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Star Topology ( Contd)

• Pros
• -Lowest Power consumption
• -Easily Scalable
• Cons
• -Not very reliable as one point of failure
• No alternate communication paths

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Mesh Topology

• Multi-Hopping Systems
• Nodes can communicate with each other directly

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Mesh Topology ( Contd)

• Pros
• Reliable as no single point of failure
• Many alternate communication paths
• Easily Scalable
• Cons
• Significantly higher power consumption
• Increased Latency

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Hybrid Topology

• Sensors are arranged in a star topology around
  the routers
• The routers arrange themselves in a mesh form

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Hybrid Topology ( Contd)

• Pros
• - Reliable as no single point of failure
• - Many alternate communication paths
• - Lower power consumption as compared to
  mesh topology
• Cons
• - Scalability becomes an issue when range
  is extended

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WSN CHARACTERISTICS

• Power consumption constrains for nodes using
  batteries or energy harvesting
• Ability to cope with node failures
• Mobility of nodes
• Dynamic network topology
• Communication failures
• Heterogeneity of nodes
• Scalability to large scale of deployment
• Ability to withstand harsh environmental
  conditions
• Ease of use
• Unattended operation
• Power consumption

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HARDWARE

• Low-power processor.
• Limited processing.
• Memory.
• Limited storage.
• Radio.
• Low-power.
• Low data rate.
• Limited range.
• Sensors.
• Scalar sensors
• temperature, light, etc.
• Cameras, microphones.
• Power.

P O W E R
Sensors
Storage
Processor
Radio
WSN device schematics
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TinyOS

• OS/Runtime model designed to manage the high
  levels of concurrency required
• Gives up IP, sockets, threads
• Uses state-machine based programming concepts to
  allow for fine grained concurrency
• Provides the primitive of low-level message
  delivery and dispatching as building block for
  all distributed algorithms

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Key Software Requirements

• Capable of fine grained concurrency
• Small physical size
• Efficient Resource Utilization
• Highly Modular
• Self Configuring

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SECURITY ATTACKS IN WSN

• DoS/Physical Layer/Jamming Transmission of a
  radio signal that interferes with the radio
  frequencies being used by the sensor network.
  Jamming the channel with an interrupting signal.
• DoS/Data Link Layer/Collision.
• DoS/Network Layer/Flooding.

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• DoS/Physical Layer/Tampering. Physical Tampering.
  Nodes are vulnerable to physical harm, or
  tampering (i.e. reverse engineering).
• DoS/Network Layer/Spoofing. Misdirection.
  Adversaries may be able to create routing loops,
  attract or repel network traffic, extend or
  shorten source routes, generate false error
  messages, partition the network, increase
  end-to-end latency, etc.

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• Sybil attack "malicious device illegitimately
  taking on multiple identities".
• Adversary can "be in more than one place at
  once" as a single node presents multiple
  identities to other nodes in the network which
  can significantly reduce the effectiveness of
  fault tolerant schemes such as distributed
  storage , dispersity and multipath.
• Sybil attacks also pose a significant threat to
  geographic routing protocols.

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• In the wormhole attack, an adversary tunnels
  messages received in one part of the network over
  a low latency link and replays them in a
  different part.
• An adversary situated close to a base station may
  be able to completely disrupt routing by creating
  a well-placed wormhole.
• An adversary could convince nodes who would
  normally be multiple hops from a base station
  that they are only one or two hops away via the
  wormhole.

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• A node replication attack involves an attacker
  inserting a new node into a network which has
  been cloned from an existing node, such cloning
  being a relatively simple task with current
  sensor node hardware.
• This new node can act exactly like the old node
  or it can have some extra behavior, such as
  transmitting information of interest directly to
  the attacker.
• A node replication attack is serious when the
  base station is cloned.

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REQUIREMENTS FOR SENSOR NETWORK SECURITY

• Data Confidentiality
• A sensor network should not leak sensor
  readings to neighboring networks.
• Encrypt the data with a secret key that only
  intended receivers possess, hence achieving
  confidentiality

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• Data authentication
• Network reprogramming or controlling sensor node
  duty cycle
• Data authentication allows a receiver to verify
  that the data really was sent by the claimed
  sender.
• Informally, data authentication allows a receiver
  to verify that the data really was sent by the
  claimed sender.

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• Data Integrity
• Data integrity ensures the receiver that the
  received data is not altered in transit by an
  adversary.
• Data Freshness
• Informally, data freshness implies that the data
  is recent, and it ensures that no adversary
  replayed old messages.

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• Two types of freshness weak freshness, which
  provides partial message ordering, but carries no
  delay information, and strong freshness, which
  provides a total order on a request-response
  pair, and allows for delay estimation.
• Weak freshness is required by sensor
  measurements, while strong freshness is useful
  for time synchronization within the network.

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SECURITY PROTOCOLS FOR WSN

• SPINS Security Protocols For Sensor Networks
• SPINS has two secure building blocks SNEP and
  µTESLA.
• SNEP includes data confidentiality, two-party
  data authentication, and evidence of data
  freshness.
• µTESLA provides authenticated broadcast for
  severely resource-constrained environments.

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• SNEP Sensor Network Encryption Protocol
• SNEP provides a number of following advantages.
• It has low communication overhead as it only adds
  8 bytes per message.
• It uses a counter, but avoids transmitting the
  counter value by keeping state at both end
  points.
• SNEP achieves semantic security, which prevents
  eavesdroppers from inferring the message content
  from the encrypted message.
• Finally, SNEP protocol offers data
  authentication, replay protection, and weak
  message freshness.

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• SNEP offers the following properties
• Semantic security Since the counter value is
  incremented after each message, the same message
  is encrypted differently each time.
• Data authentication If the MAC verifies
  correctly, the receiver can be assured that the
  message originated from the claimed sender.

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• Replay protection The counter value in the MAC
  prevents replaying old messages.
• Weak freshness If the message verified
  correctly, the receiver knows that the message
  must have been sent after the previous message it
  received correctly (that had a lower counter
  value
• Low communication overhead The counter state is
  kept at each end point and does not need to be
  sent in each message.

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• µTESLA
• A sender will broadcast a message generated with
  a secret key.
• After a certain period of time, the sender will
  disclose the secret key.
• The receiver is responsible for buffering the
  packet until the secret key has been disclosed.
• After disclosure the receiver can authenticate
  the packet, provided that the packet was received
  before the key was disclosed.
• Limitation of µTesla is that some initial
  information must be unicast to each sensor node
  before authentication of broadcast messages can
  begin.

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• TINYSEC
• It is designed as the replacement for the
  unfinished SNEP, known as TinySec.
• A major difference between TinySec and SNEP is
  that there are no counters used in TinySec.
• Single shared global cryptographic key.
• For encryption, it uses CBC mode with cipher text
  stealing , and for authentication, CBC-MAC is
  used. TinySec XORs the encryption of the message
  length with the first plaintext block in order to
  make the CBC-MAC secure for variably sized
  messages
• Link layer encryption and integrity protection ?
  transparent to applications

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• MINISEC
• It is a secure network layer protocol that claims
  to have lower energy consumption than TinySec
  while achieving a level of security which matches
  that of Zigbee.
• A major feature of MiniSec is that it uses
  offset codebook (OCB) mode as its block cipher
  mode of operation, which offers authenticated
  encryption with only one pass over the message
  data.
• Normally two passes are required for both secrecy
  and authentication.

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• LEAP Localized Encryption And Authentication
  Protocol
• LEAP is designed to support secure communications
  in sensor networks therefore, it provides the
  basic security services such as confidentiality
  and authentication.
• LEAP supports the establishment of four types of
  keys for each sensor node an individual key
  shared with the base station, a pairwise key
  shared with another sensor node, a cluster key
  shared with multiple neighboring nodes, and a
  group key that is shared by all the nodes in the
  network.

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• ZIGBEE
• Zigbee Coordinator acts as Trust Manager, which
  allows other devices to join the network and also
  distributes the keys.
• It plays the three roles as follows
• - Trust manager, whereby authentication of
  devices
• requesting to join the network is done.
• - Network manager, maintaining and
  distributing
• network keys.
• - Configuration manager, enabling
  end-to-end
• security between devices.

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• 802.15.4
• Provides link layer security services, and has
  three modes of operation, unsecured, an Access
  Control List (ACL) mode and secured mode.
• In unsecured mode, as the name implies, no
  security services are provided.
• In ACL mode the device maintains a list of
  devices with which it can communicate.
  Communication from devices not on the list is
  ignored. No cryptographic security.

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• Secured mode offers seven security suites and
  depending on which is used any of four security
  services are offered,
• access control
• data encryption
• frame integrity
• sequential freshness.

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• References 
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• http//en.wikipedia.org/wiki/Wireless_sensor_netwo
  rk

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• THANK YOU