IoMT image encryption application based on homogeneous multistability and adaptive orbit-switching key update
Rui Li, Sen Zhang, Yichen Wang, Zi Wang, Guohuan Hua, Xin Ding · AEU - International Journal of Electronics and Communications · 2026
Internet of Things (IoT) nodes with security requirements consistently demand lightweight and reliable encryption algorithms. Existing mainstream methods usually generate encryption sequences through chaotic pseudorandom number generators. However, in many current schemes, the chaotic model is separated from the encryption pipeline, making it difficult to fully exploit the intrinsic properties of the chaotic dynamics. For Internet of Medical Things (IoMT) encryption, this paper proposes a lightweight image encryption mechanism based on a homogeneous multistable chaotic map. According to the characteristics of the chaotic map, a stochastic orbit-switching key update mechanism with tunnel-triggered rules and adaptive thresholds is designed to improve the randomness and nonlinearity of the keystream. The generated keystream then drives neighborhood diffusion and a dual-layer scrambler to disturb image blocks and intra-block structural features. The evaluation considers histogram distribution, adjacent-pixel correlation, entropy, NPCR, UACI, cropping, Gaussian noise, and embedded execution time. The proposed scheme is deployed on an STM32H7 series microprocessor. Encryption performance tests show that this scheme provides good security.