Abstract:Abstract: With the deployment and development of strategic initiatives such as "Strong Smart Grid" and "Ubiquitous Power Internet of Things," a large number of power collection devices, robots, and monitoring cameras are being applied in distribution network operation scenarios. Therefore, in view of the factors such as the large number of distribution network terminals and the diverse and complex distribution network operation environment, how to design a suitable communication architecture is particularly important for ensuring the safe and stable transmission of distribution network data. Firstly, this article compares and analyzes MQTT, CoAP, and HTTP, which are currently popular Internet of Things platform communication protocols, from multiple perspectives, and designs a novel communication architecture for power distribution Internet of Things. Furthermore, in response to security requirements, we propose the MQTT-SM4 mask-assisted encryption algorithm based on the national cryptographic algorithm SM4 to encrypt and transmit information in the power distribution Internet of Things. The mask key and message key required for this encryption are obtained through session key negotiation, and the round key is calculated by the two keys together for encryption. Through encryption testing and security analysis of the MQTT-SM4 mask-assisted encryption algorithm, simulation results show that the design scheme in this article can effectively improve the communication security and stability of the power distribution Internet of Things.