Certificateless authenticated encryption with keyword search: Enhanced security model and a concrete construction for industrial IoT

The Industrial Internet of Things (IIoT) represents a variety of IoT applications in the industrial sector of economy and is heavily underpinned by computational capabilities of cloud computing to reduce the cost of on-demand services. However, cloud computing does not protect the privacy of the outsourced data unless some form of encryption is applied. Recently, some Certificateless Authenticated Encryption with Keyword Search (CLAEKS) schemes have been proposed. However, it is known in the literature that the security of these schemes is proved based on a weak security model. In this paper, we first provide a more powerful and realistic security model for CLAEKS schemes. Then, we propose a new CLAEKS scheme and prove its security in the enhanced security model. The comparison results show that the proposed CLAEKS scheme is the only existing searchable encryption scheme in the certificateless setting that is secure in the enhanced security model.