Permutation-based outsourced private set intersection cardinality protocol

Private Set Intersection Cardinality protocol (PSI-CA) plays an important role in secure multi-party computation, which requires two players to compute the intersection size with no additional information displayed. In practice, people use cloud servers to increase the computational efficiency of the parties, but the current article can only be implemented in a non-collusion setting, i.e., there can be no collusion between the parties involved, and additional information may be leaked when the parties collude. We give a securely Outsource unbalanced Private Set Intersection Cardinality protocol to solve this problem. This protocol can resist the collusion problem between the cloud sever and the players by using Permute + Share and Permuted OPRF to hide the players data information, and gives the correctness proof and security proof in the real-ideal model to verify the protocol’s feasibility. The protocol is implemented through experimental simulation and test the performance of the protocol under different set sizes respectively, meanwhile, comparison of our protocol with current outsourced PSI-CA protocols, this paper has advantages in respect of communication cost and runtime.