Shared Cross-Prediction Neural Network for Efficient Key Generation in IoT Networks
Anas Alashqar, Ehsan Olyaei Torshizi, Raed Mesleh, Werner Henkel · 2025
Physical layer secret key generation (PSKG) lever-ages the reciprocal properties of wireless channels to establish cryptographic keys between legitimate users. However, in time-division duplex (TDD) systems, this reciprocity can be compromised by hardware imperfections and channel noise, complicating the key generation process. To address these challenges, we propose a shared cross-prediction neural network (SCP-NN) model that operates in an unsupervised manner, eliminating the need for perfect channel state information (CSI). Specifically, the proposed SCP-NN model employs a cross-prediction strategy that minimizes the difference between the predicted channels of legitimate users, ensuring that the outputs converge toward each other. Furthermore, we present a comprehensive PSKG procedure that leverages the SCP-NN architecture to extract key information from the phase characteristics of the channel frequency responses. Experimental results demonstrate that the proposed SCP-NN significantly reduces the key disagreement ratio (KDR), providing a robust and effective solution for secure key generation in dynamic IoT environments.