BACASE-SH: Blockchain-based authenticated certificate-less asymmetric searchable encryption for smart healthcare

Nowadays, smart healthcare and Electronic Health Record (EHR) play a significant role in simplifying the experience of medical treatment and cuts down the trivial work of paramedics. However, this poses significant challenges for organizations, including the management, transfer and protection of EHR which is vital for correct detection. To overcome these challenges, cloud computing presented which offers various attractive features for EHR management such as data availability, elasticity, and ubiquitous computation. However, the use of cloud computing introduces confidentiality and privacy concerns which can lead to human health threat. A trivial solution for this problem is encryption which makes searching a desired document infeasible, more specifically in big data scenarios. Although searchable encryption is a candidate solution, it suffers from keyword guessing attacks, malicious service providers, lack of trust, data integrity, and fairness. In this paper, we propose BACASE-SH framework that leverages blockchain technology to EHR integrity and availability insurance, fair payment, and establish trust among the involved parties. Moreover, we present a certificate-less authenticated asymmetric searchable encryption scheme to address challenges such as data owner (patient) and data user (physician) identity and keyword guessing attacks. The scheme is implemented using a smart contract, and the evaluation results show its efficiency.