Quantum Multiparty Privacy Set Intersection Cardinality

In this brief, we present a novel quantum protocol for Multiparty Privacy Set Intersection Cardinality (MPSI-CA) and design the corresponding quantum circuits. The proposed protocol demonstrates two primary aspects of quantum advantage: the parallelism of quantum computing and the randomness of quantum measurement. Compared with the classical related protocols, the proposed MPSI-CA protocol can ensure higher security (i.e., unconditional security) and achieve better communication complexity (i.e., O(t
²
)).