RSS-based secret key generation in underwater acoustic networks: advantages, challenges, and performance improvements

Due to the broadcast nature of acoustic channel, underwater acoustic networks (UANs) face threats of eavesdropping and fake data injection. How to secure acoustic communications in a UAN is becoming an important but challenging topic. Among different secret key approaches, received-signal-strength (RSS)-based key generation is particularly appealing, as it can eliminate the need to deploy an additional key distribution center, making it a more attractive method than conventional symmetric key cryptography in resource-constrained UANs. A variety of RSSbased key generation approaches have been designed for wireless radio networks. However, no attempt has been made to evaluate their performance in underwater environments. In this article, we provide an overview of the advantages of RSS-based key generation and explore the major challenges from the unique features of underwater systems through experiment results of sea trails. Meanwhile, we discuss viable solutions to improve the performance of RSS-based key generation in oceans.