Time-Specific Integrity Service in MQTT Protocol

Message Queuing Telemetry Transport (MQTT) is a classic transmission protocol in IoT scenarios, where a subscriber subscribes to the messages, and a publisher publishes the message to the broker, who then sends the message to the subscriber. In MQTT, it is essential to ensure its security in the temporal domain. On one hand, some messages are time-sensitive, so their integrity should only be valid in a determined time interval. On the other hand, when the subscriber is out of the service, his key should not be able to verify the message, which is known as subscriber validity. This paper discusses the time-specific integrity service in the MQTT protocol. To solve the problem, we propose Time-specific Signcryption (TSSC) and the Dynamic Time-specific Signature (DTSS). Furthermore, a Progressive Dynamic Time-specific Signature scheme (Pro-DTSS) is proposed to save communication costs. The theoretical and experimental results show that our proposed schemes are more efficient than the existing solutions.