With the rapid development of high-tech with each passing day, the cross fusion and deep correlation among the Internet of Things, big data, and artificial intelligence are implemented. The Internet of Things is fully integrated into all aspects of our life and work as well as social development. At present, the most widely used and mainstream protocol of the Internet of Things is the message queuing telemetry transport (MQTT) protocol, whose inherent advantages of low overhead and low bandwidth have contributed to the access of a large number of Internet of Things devices to the network. However, in the era of the Internet of Everything, “freedom, controllability, safety, and credibility” are the concepts and criteria of industrial development. Many researchers have proposed MQTT-based design schemes for security algorithms. Regarding the paper titled “Data encryption transmission algorithm Based on MQTT”, however, its core algorithm is found to be at risk of key leakage. Therefore, this study points out the defects of this core algorithm and proposes three MQTT-SE algorithms respectively based on symmetric encryption, public key, and mutual verification of public key certificates. These algorithms can achieve the purpose of high-performance and safe encryption transmission even in a low performance MQTT transmission environment.