Biometric Template Protection for Dynamic Time Warping-based User Authentication

A DTW-based biometric user authentication system needs a DTW template to set up a warping function for a query biometric. In addition, a matching template is required to examine similarity. In this paper, we present a hardened template to protect the DTW template. For the matching template, it is protected by cryptographic framework. We compare our scheme with a transformation approach and an unprotected. We evaluate the scheme with a public dataset: the MIT mobile device speaker verification corpus. The experimental results show that the proposed scheme outperforms the transformation approach. Moreover, it is slightly degraded when we compare it with the unprotected template. We also show that an adversary can exploit the transformed template to gain access to the system which does not differ from the unprotected approach.