Research on a Lightweight SM4 Algorithm-Driven Secure Communication Mechanism for Communication Links

Secure communication for resource-constrained embedded devices must simultaneously satisfy cryptographic compliance, low-latency transmission, and robustness against link disturbances, which makes lightweight deployment of national cryptographic algorithms a critical issue in edge and industrial communication systems. To address this problem, a lightweight SM4-based communication security mechanism is developed for heterogeneous embedded links. The proposed method integrates S-box structure compression, round-function optimization, key-scheduling reconstruction, module trimming, and interface adaptation to construct an efficient encryption/decryption framework that supports UART, CAN, and BLE communication environments. The significance of this study lies not only in reducing the computational and storage burden of SM4, but also in enabling practical deployment of a national-standard encryption mechanism in low-power, real-time, multi-interface embedded platforms. Experimental results on the STM32L432KC platform show that, under the BLE link, the proposed scheme achieves an average encryption latency of 165.8 μs and a throughput of 8.42 KB/s. Compared with existing SM4 and AES implementations, the method provides better delay-throughput performance while maintaining strong anti-interference capability and state-recovery resilience under multiple attack and error-injection scenarios. These results indicate that the proposed mechanism is suitable for secure communication tasks requiring both lightweight implementation and link-level adaptability in embedded systems.