Efficient Physical-Layer Secret Key Generation for Satellite IoT System

The application of physical-layer secret key generation (PLSKG) to satellite IoT systems faces several challenges, including long channel coherence times, strong spatial channel correlation, and stringent constraints on computational and energy resources. To address these issues, this paper proposes three novel approaches: a stacked intelligent metasurface (SIM)-aided decorrelation, a data-aided PLSKG mechanism for imposing randomness, and a new lightweight information reconciliation (IR) process. Simulation results demonstrate that the proposed SIM assistance and data-aided processing effectively suppress information leakage to eavesdroppers, even under highly correlated channel conditions, while significantly reducing computational complexity due to the proposed IR.