Computations on Private Sets and their Application to Biometric based Authentication Systems

Abstract

In this paper we investigate the concept of cancelable biometrics and propose a new scheme for user authorisation providing anonymity based on privacy-preserving computations on sets. We define a problem called (t;n) -Threshold Subset Problem and apply it to a biometric-based security system. Our solution implements biometric template protection based on one-way transformations and Bloom filters. Users authentication data is stored in form of a whitelist and the authorisation process is based on a zero-knowledge proof approach. Using oblivious polynomial evaluation (OPE) a legitimate user is able to recreate a secret polynomial and answer the challenge send by a verifier. We assume that biometric data can be acquired and digitized to the form of a vector representation.