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Table of contents
Key Predistribution
General Working
Explanation of Key Predistribution Schemes 
Explanation of Shared key discovery
Explanation of Path key establishment
Frequently Asked Questions
Key predistribution: What is it? 
What does WSN placement entail? 
What are a wireless sensor network's three primary components? 
What are the four techniques for distributing public keys? 
What is the wireless key? 
Last Updated: Mar 27, 2024

Key Predistribution in Sensor Networks

Author Yashi Agarwal
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Distributed sensors that track physical or environmental parameters like temperature, sound, pressure, and so forth make up a wireless sensor network. The monitored data is then sent via the network to the central location. Future uses of wireless sensor networks include the military, law enforcement agencies, research, and many more. 

key predistribution in sensor network

The fundamental problem with wireless sensor networks is security. Multiple data packet types, routing protocol packets, and key management protocol packets are organized by sensor networks. Many key types are utilized to provide secure data communication via the network.

Key Predistribution

There are numerous methods for establishing secure node-to-node communication. Key predistribution is the strategy that works the best. The key predistribution method involves preloading specific keys into each sensor ahead of deployment. Before deployment, a set of keys is allocated to each sensor node from the sizable pool of keys. When two nodes are deployed and have at least one common key, a communication link can be established between them. Key predistribution strategies rely on various WSN properties to deliver superior results. They are resilience and local and global connectivity.


A key predistribution strategy essentially consists of three phases:

• Key distribution 

• Shared key discovery 

• Path-key establishment 

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General Working

Secret keys are generated and inserted into sensor nodes at these stages. Then, each sensor node looks around its communication range for additional nodes to find and communicate with. A secure connection has been created when two nodes identify one or more shared keys—which vary depending on the key predistribution scheme—and communicate on that link. Once a connected graph has been created using these relationships, routes can then be identified. Three categories categorise all of the important predistribution approaches. These techniques are:

1) Probabilistic

2) Deterministic 

3) Hybrid 

Explanation of Key Predistribution Schemes 

  • The basic scheme is another name for the random key predistribution technique. Eschenauer et al. proposed this method. 
  • Every sensor node receives a random selection of keys from a big pool that are then stored there. 
  • Any two nodes that discover shared keys can utilize these keys for safe communication. The configuration of the communication keys requires three steps.
  • Each sensor node carries k unique keys randomly selected from a large key pool. 
  • Key chain length L and key pool size K make up the key pool. 
  • The key chain is made using a keyed hash method to establish seed and a special generation key gi.

As a result, Kci, l = H seed, gi is used to determine the lth key from the key chain. The key rings are assigned to each node during the key ring loading phase. It is divided into two halves, R1 and R2, each of which has a set of randomly selected keys from several key chains. A keyring is a collection of k keys, and each key has an identical identification number. The shared-key discovery phase starts when the sensor nodes are set up in the identified area. Each node in this phase determines the radio-range neighbors that it shares mutual keys.

Links are established between nodes within the radio range and have standard keys after the shared-key discovery stage. This technique creates a key predistribution strategy using the random-graph theory.

Explanation of Shared key discovery

  • Once the sensor nodes have been placed in their proper locations, each one starts looking for neighbors with whom it may exchange keys. 
  • It is possible to determine whether two nodes share a common key in a number of different ways. 
  • To other nodes, the nodes broadcast a list of the key identifiers. 
  • A node can use this key for a secure communication range to find another node to communicate with if it learns to share a common key with a certain node. 
  • A secure link is created when two nodes find one or more common keys—which differ in each key predistribution scheme.
  • Then, the two nodes communicate with one another via that link. Once a connected graph has been created using these relationships, routes can then be identified

Explanation of Path key establishment

  • When two nodes cannot share a common key, the path key establishment stage acts as a bridge. 
  • For instance, if node A wishes to interact with the node, there needs to be a shared key between the two nodes. 
  • To communicate with node B, node A can send a message to node C. 
  • Then, an encrypted message is created using the common key shared by nodes A and C. 
  • If node C shares a common key with node B, it can also generate a pairwise key for nodes A and B. hence it acts like a key distribution center

Frequently Asked Questions

Key predistribution: What is it? 

The key predistribution method is used to distribute keys to various sensor nodes before deployment. As a result, following deployment, these sensor nodes construct a network by forging secure connections between various nodes using their common secret keys. 

What does WSN placement entail? 

Range-based positioning and range-free positioning are the two types of WSN positioning technology. The former calculates the position coordinates of unknown nodes using the trilateration or the triangular positioning method after measuring the straight-line distance or angle information between nodes.

What are a wireless sensor network's three primary components? 

It is employed to gather data generated by the Sensors and transmit it to the WLAN access point. It has an external memory, transceiver, microprocessor, and power source. 

What are the four techniques for distributing public keys? 

  • Public announcement.
  • Publicly available directory.
  • Public-key authority.
  • Public-key certificates.

What is the wireless key? 

In essence, it is the password or other information required to access a local area network. Most people know network security keys because they are used at home to connect to their Wi-Fi network. Users can create a secure connection and stop unauthorized access to the network using network security keys.


This article discussed everything about Key Predistribution in Sensor Networks. We started with explaining key predistribution general working of it, then an explanation of key predistribution schemes shared key discovery and path key establishment.

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