Design of a novel optimization framework for the analysis of the impact of critical nodes on network lifetime of underwater acoustic sensor networks utilizing private key cryptography

Oceans and seas cover approximately 70% of the earth's surface. However, there are still a lot of unknowns about underwater life, which means there are a lot of opportunities for exploration. Semiconductor technology progressed rapidly toward the end of the twentieth century, lowering production costs dramatically. Due to harsh conditions such as high pressure, abrasion, and other factors, designing sensors suitable for such environments is a difficult and costly task. Furthermore, deploying and maintaining sensors in these areas necessitates highly skilled and expensive labor. Underwater Acoustics Sensor Networks (UASN) are usually deployed sparsely in harsh underwater environments. Their access is restricted once the network is deployed. The encryption of the data packets ensures the security of the data sent between the nodes. Because sensor nodes have limited memory, each node only has a subset of the keys distributed across the entire network. In a secure communication scheme, two nodes must not only be at a certain distance from each other to send data, but they must also share the same secret key. As a result, only a portion of the physical links are available and can be used for secure communications. Since the sink node contains all the secret keys in the pool, the sensor nodes can send the data they collect directly to the sink node. In addition, they can send their gathered data to the sink node via other sensor nodes that have established a secure connection. Due to the secure connection constraint, available data transmission paths are limited, and nodes are unable to use the best transmission path when transferring data packets, consuming more energy than they should. Because the sensor's batteries are limited, the network's lifetime shortens as more energy is consumed for transmission. The effects of incapacitating the critical node on network lifetime in UASNs with incomplete secure connectivity were investigated using a linear programming (LP) model with various parameters such as network size, key sharing probabilities, and the number of critical nodes.