Lattice-based public-key encryption with conjunctive keyword search in multi-user setting for IIoT

Most traditional Public-Key Encryption with keyword Search (PEKS) schemes are suffering a tremendous threat occasioned by the burgeoning of quantum computing since these schemes are derived from the bilinear pairing. For the sake of preserving the security of data outsourced by the Industrial Internet of Things (IIoT), a novel efficient PEKS scheme based on lattice assumption is proffered, and it can achieve security against quantum computing attacks. Also, it supports both multi-user and conjunctive keyword search. Besides, we adopt broadcast encryption technology to address the enormous storage cost of keywords ciphertext in a multi-user setting. Our scheme only needs to generate one ciphertext for all data users, thus significantly reducing the storage cost. Lastly, its performance is analyzed theoretically and experimentally. Experimental simulation results demonstrated the superiority of our algorithms in multi-user and multi-keyword scenarios. The scenario of 100 keywords in keyword encryption for 10–100 users always costs about 0.0204 s, and the storage cost keeps at 81.7 KB–84.7 KB.