Efficient Private Set Intersection Cardinality in the Presence of Malicious Adversaries

In this paper, we study Private Set Intersection Cardinality (PSI-CA) protocols and propose two new constructions of PSI-CA. While one of these constructions is secure in the standard model, the other one is secure in the random oracle model (ROM). The security is under the Decisional Diffie-Hellman (DDH) assumption against malicious adversaries. Our proposed PSI-CA protocols are the first to achieve linear communication and computation complexities and secure against malicious adversaries. Furthermore, each of our PSI-CA constructions can be converted to PSI without losing any of the above stated properties.