Fingerprint template protection using minutia-pair spectral representations

Storage of biometric data requires some form of template protection in order to preserve the privacy of people enrolled in a biometric database. One approach is to use a Helper Data System. Here it is necessary to transform the raw biometric measurement into a fixed-length representation. In this paper, we extend the spectral function approach of Stanko and Škorić (IEEE Workshop on Information Forensics and Security (WIFS), 2017) which provides such a fixed-length representation for fingerprints. First, we introduce a new spectral function that captures different information from the minutia orientations. It is complementary to the original spectral function, and we use both of them to extract information from a fingerprint image. Second, we construct a helper data system consisting of zero-leakage quantisation followed by the Code Offset Method. We show empirical data on matching performance and entropy content. On the negative side, transforming a list of minutiae to the spectral representation degrades the matching performance significantly. On the positive side, adding privacy protection to the spectral representation can be done with little loss of performance.