Physical Layer Group Key Generation for Ambient Power-enabled Internet of Things

Ambient Power-enabled Internet of Things (AIoT) is expected to be a key technology for future 6G to support green and sustainable development. Developing lightweight security mechanisms to accommodate the extremely low power consumption of AIoT devices is of vital importance. Physical layer key generation (PLKG) is expected to be a promising security technology for AIoT. Considering the widespread application of one-to-many communication paradigm in AIoT systems, in this paper, we propose a physical layer group key generation (PLGKG) scheme to support the secure group communications among multiple AIoT devices. By designing the precoding weight coefficient of the reader, multiple AIoT devices can receive the same key source at the same time, and thus obtain the common group key. The system security is analyzed and the achievable group key rate (GKR) is also derived. Simulation results show that the proposed scheme not only reduces the time overhead of group key generation, but also achieves the lower group key disagreement ratio (GKDR).