Tag-Based Secure Set-Intersection Protocol and Its Application to Privacy-Enhancing Biometrics

The secure set-intersection protocol is a cryptographic protocol that retrieves the intersection of two or more datasets without revealing any additional information apart from the intersection data. In this paper we formalize the secure matching tag, which is frequently used in the existing secure set-intersection protocols, and propose applying the tag to privacy-enhancing biometrics. Due to the index property of the tag, the proposed protocol can efficiently match the biometric data of a certain user from among a large amount of encrypted biometric data of users without entering the user ID.