An Efficient Multi-Party Private Set Intersection Protocol

Privacy Set Intersection (PSI) is an important Secure Multi-Party Computation (SMC) technique that allows participants to securely compute the intersection of their data sets without revealing any other information. To address the unfairness issues present in existing protocols, this paper proposes a fair multi-party PSI protocol based on Three-Hash Garbled Cuckoo Table (3H-GCT) and secret sharing. The protocol uses 3H-GCT as a data structure to store the data of each participant and employs secret sharing and share permutation techniques to protect data privacy, preventing the leakage of individual elements during the interaction. The core of the protocol lies in the cloud server performing bitwise XOR operations on the 3H-GCTs of each participant to compute the intersection, and then sending the intersecting 3H-GCT to all participants, ensuring the fairness of the protocol. Correctness analysis and security proofs show that the protocol is secure in a semi-honest environment. Experimental data indicates that the protocol has lower communication costs and computation time compared to existing protocols.