A New Protocol for Semi‐quantum Private Set of Intersection and Union Mixed Cardinality for Any Tripartite Based on Bell States

The cardinality of the private set allows multiple parties to jointly compute the cardinality of the intersection and union without revealing their respective private sets. It plays an important role in data mining and data analysis to protect privacy. However, existing studies only focus on computing the cardinality of the intersection or union of private sets. To extend its application in various scenes, a private‐set intersection and union mixed cardinality protocol are proposed for any tripartite based on Bell states for the first time. During the protocol, participants are supposed to be semi‐quantum to reduce the consumption of quantum resources and improve the realizability of the protocol. Furthermore, correctness and security analysis show that the protocol can withstand internal and external attacks. Additionally, the IBM Quantum Simulator (IBMQS) is also applied to illustrate the fundamentals of the protocol and verify the availability of the protocol. The results are expected have positive effects on the further development of secure multiparty computation.