A Secure Transmission Scheme With Efficient and Lightweight Group Key Generation for Underwater Acoustic Sensor Networks

Physical-layer-based key generation is a promising technique for enhancing the security of underwater acoustic sensor networks (UASNs) and has been widely studied in point-to-point scenarios. However, when it is extended to multiuser scenarios in UASNs, its overhead costs are high and the information transmitted is prone to leakage. In this study, a group key generation scheme called STO-GSKG is proposed to share a secret key for multiple users. The pairwise keys extracted from the acoustic channels between the cluster head and the member nodes are used to protect the distribution of group keys. Specifically, to reduce the time consumption and communication overhead required for probing channels, a spatial-temporal reuse-based channel probing method that exploits large delays of underwater acoustic (UWA) channels is proposed. Then, secret bit sequences with high consistency and strong randomness are generated using a joint design that utilizes the multipath characteristics of UWA channels and introduces time-varying channel obfuscation information. The performance of the proposed scheme is evaluated through simulation and field experiments. The results show that the STO-GSKG scheme is more effective and robust than existing methods.