Lightweight multiparty privacy set intersection protocol for internet of medical things

Abstract

The development of privacy-preserving data exchange protocols through Privacy Set Intersection (PSI) protocols has emerged as a critical enabler for secure information exchange in the Internet of Medical Things (IoMT), particularly for applications requiring coordinated data analysis across distributed healthcare systems. Current PSI implementations face two fundamental limitations: a lack of efficient multi-user extension capabilities and vulnerability to quantum computing threats, which significantly limit their use in modern smart healthcare platforms. In this paper, we present a new construction based on the symmetric key pseudorandom function over lattice to overcome these challenges. First, a pseudorandom generator over LWE problems is proposed to construct the pseudorandom functions (PRFs) and oblivious key–value storage (OKVS). The proposed PRF achieves 1-almost key-homomorphic. Based on the proposed PRFs and OKVS, an efficient multi-party PSI protocol is introduced. In this framework, lattice-based cryptography is implemented for PRFs operation and OKVS encoding, ensuring semantic security against quantum adversaries and collusion attacks even when untrusted cloud servers process sensitive patient data. Integration of virtual set elements with probabilistic validity checks, enabling efficient detection of data tampering while preserving protocol efficiency. The results of simulation experiments and security analysis show that the proposals achieve user privacy, collusion resistance, verification of computational results, and low computational cost.