Cooperative Secure Transmission Against Eavesdropping Attacks with Probabilistic Encryption, Channel Coding and Interleaving

Secure information transmission over IoT-based wireless sensor networks is critically influenced by the reliability of electromagnetic wave propagation and the resilience of physical-layer communications against passive eavesdropping. This paper investigates cooperative secure transmission in multi-hop and multi-relay wireless sensor networks by proposing a unified framework for intelligent eavesdropping scenarios. To effectively mitigate passive interception threats, a lightweight information-theoretic secure communication scheme is developed by modeling data processing as a communication channel and introducing a bit-level probabilistic encryption mechanism based on random bit flipping, thereby minimizing the mutual information between confidential messages and intercepted signals. Furthermore, channel coding and bit interleaving are incorporated to make brute-force recovery by eavesdroppers computationally impractical, particularly in high-speed wireless transmission environments, without requiring prior knowledge of the legitimate user’s complete channel state information. An LLR-based fuse-then-decode decision rule is derived, and a low-complexity suboptimal fusion strategy based on the Min-Sum Algorithm is proposed to balance decoding efficiency and communication reliability. Simulation results verify the theoretical analysis and demonstrate that the proposed framework provides robust and efficient secure transmission performance for energy-constrained wireless sensor networks while offering valuable guidance for physical-layer security and electromagnetic-aware wireless communication systems.