MT-PRO: Multibiometric Template Protection Based On Homomorphic Transciphering

Reliable authentication of individuals is the foundation of trusted digital interaction. Biometrics lend themselves ideally to this goal. However, biometric data must be protected under computation according to European laws and international standards. Over the past ten years, fully homomorphic encryption has become a popular tool for biometric template protection. However, it comes with the security risk of cryptographic key material, which requires careful management and could be leaked, leaving the stored templates vulnerable to attacks. To meet this challenge, we present the novel MT-PRO protocol utilising homomorphic transciphering to improve the security of such systems against offline decryption attacks. Our protocol does not impair the biometric performance and allows for multi-biometric comparisons of fixed-length feature representations. Furthermore, we evaluated our protocol on public data sets with open-source implementation available at https://github.com/dasec/MT-PRO and discuss its real-world application potential.