Physical-Layer Secret Key Generation for Dual-Task Scenarios

Physical-layer secret key generation (PSKG) provides a lightweight way for group key (GK) sharing between wireless users in large-scale wireless networks. However, most of the existing works in this field consider only group communication. For a commonly dual-task scenario, where both GK and pairwise key (PK) are required, traditional methods are less suitable for direct extension. For the first time, we discover a security issue with traditional methods in dual-task scenarios, which has not previously been recognized. We propose an innovative segment-based key generation method to solve this security issue. We do not directly use PK exclusively to negotiate the GK as traditional methods. Instead, we generate GK and PK separately through segmentation which is the first solution to meet dual-task. We also perform security and rate analysis. It is demonstrated that our method is effective in solving this security issue from an information-theoretic perspective. The rate results of simulation are also consistent with the our rate derivation.