Lightweighted Secure Searching Over Public-Key Ciphertexts for Edge-Cloud-Assisted Industrial IoT Devices

For the industrial Internet of Things (IIoT), public-key encryption with keyword search (PEKS) is a type of applicable and promising encryption technique to maintain the data stored in clouds secure and searchable. To further improve the efficiency of searching, it is popular to introduce edge computing near the IIoT as the substitute for a cloud. However, the straightforward collaboration of the two techniques performs negatively in latency-sensitive applications since the sluggish encryption of PEKS by IIoT devices negates the instant reaction of edges. To meet this challenge, in this article, we exploit the capability of the edge-cloud architecture and propose a lightweight-designed scheme called edge-aided searchable public-key encryption (ESPE). It allows IIoT devices to delegate their costly cryptographic operations to the nearby edge for fast computing and guarantees that all outsourced ciphertexts are semantically secure. Consequently, ESPE accelerates the corresponding ciphertext procedures on edges and saves over 70% encryption cost of an IIoT device.