## Cryptology ePrint Archive: Report 2021/1057

An Efficient Data Protection Scheme Based on Hierarchical ID-Based Encryption for Message Queueing Telemetry Transport

Chun-I Fan and Cheng-Han Shie and Yi-Fan Tseng and Hui-Chun Huang

Abstract: As Internet of Things (IoT) thriving over the whole world, more and more IoT devices and IoT-based protocols have been designed and proposed in order to meet people's needs. Among those protocols, message queueing telemetry transport (MQTT) is one of the most emerging and promising protocol, which provides many-to-many message transmission based on the publish/subscribe'' mechanism. It has been widely used in industries such as the energy industry, chemical engineering, self-driving, etc. While transporting important messages, MQTT specification recommends the use of TLS protocol. However, computation cost of TLS is too heavy. Since topics in a broker are stored with a hierarchical structure, In this manuscript, we propose a novel data protection protocol for MQTT from hierarchical ID-based encryption. Our protocol adopts the intrinsic hierarchical structures of MQTT, and achieves constant-size keys, i.e. independent of the depth in hierarchical structures.

Category / Keywords: cryptographic protocols / Hierarchical ID-Based Encryption, Message Queueing Telemetry Transport, MQTT, Data Protection.