A Self-Healing Pairwise Key Pre-Distribution Scheme in IoT-based WSNs

Wireless Sensor Networks (WSNs) are becoming integral to Internet of Things (IoT) applications. This emergence of the WSNs requires greater awareness of the security of IoT, which makes it inevitable to secure the communication medium of the WSNs. One way of securing the communication medium is to encrypt the data sent over the WSNs, requiring the usage of cryptographic materials to achieve the secrecy of the exchanged data between the sensor nodes. The main component of the cryptographic materials needed is the keys used to encrypt and decrypt the data. Symmetric pairwise keys are particularly convenient for resource-constrained networks like IoT-based WSNs as they ensure security while conserving resources. However, existing key management solutions based on symmetric cryptosystems are vulnerable to node compromising attacks. Another important aspect of WSNs is the addition of new sensor nodes (postdeployment) either periodically or depending on the use case, which means new symmetric pairwise keys must be provided to communicate with newly added sensor nodes. For this purpose, a new key pre-distribution scheme named POK (adaPtive and rObust Key pre-distribution) is presented in this paper. POK improves the way keys are generated and pre-loaded in the sensor nodes. The main idea of the POK is that newly added sensor nodes will be pre-loaded with pairwise keys computed by using a hash function and having knowledge of the number of future postdeployments. Comparison study with related works concludes that POK offers less communication overhead and doesn’t require time synchronization leading to an energy-efficient scheme. Also, POK decreases the impact of node compromising attacks and ensures the self-healing property where compromised nodes have a short time effect on the network and newly deployed nodes are not affected.