Edge-Based Blockchain Architecture for Event-Driven IoT using Hierarchical Identity Based Encryption

IoT (Internet of Things) sensors usually generate a large amount of data that is shared with a centralized cloud to provide various services. Traditional IoT architecture is heavily centralized, where data stored in a cloud environment is prone to several kinds of threats. As such, both data generated by sensors as well as IoT network shall be protected. Blockchain is an emerging technology that can be used in a wide spectrum of applications for better protection. However, the traditional blockchain protocol for Bitcoin cannot be used for IoT data protection because Bitcoin is a payment system, and the IoT ecosystem has a different architecture and requirements. Hence, more suitable blockchain architecture and encryption schemes for IoT are needed. In this paper, we propose a privacy-preserving blockchain architecture for IoT using Hierarchical Identity Based Encryption (HIBE). The proposed architecture fits well with event-driven IoT devices and uses the edge and the cloudlet computing paradigm as well as HIBE to preserve the privacy. Furthermore, the efficiency of the proposed architecture is demonstrated using a real-life case, namely, traffic speed radars. The security of the proposed architecture is analyzed and is verified through theoretical analysis that considers the existence of a malicious adversary. The performance of the proposed architecture is evaluated by conducting extensive experiments using the Contiki OS. The experimental results provide the system and network performance of the proposed architecture.