Biometrics security is a dynamic research area spurred by the need to protect
personal traits from threats like theft, non-authorised distribution, reuse and
so on. A widely investigated solution to such threats consists in processing
the biometric signals under encryption, to avoid any leakage of information
towards non-authorised parties. In this paper, we propose to leverage on the
superior performance of multimodal biometric recognition to improve the
efficiency of a biometric-based authentication protocol operating on encrypted
data under the malicious security model. In the proposed protocol,
authentication relies on both facial and iris biometrics, whose representation
accuracy is specifically tailored to trade-off between recognition accuracy and
efficiency. From a cryptographic point of view, the protocol relies on SPDZ a
new multy-party computation tool designed by Damgaard et al. Experimental
results show that the multimodal protocol is faster than corresponding unimodal
protocols achieving the same accuracy
