Abstract: The popularity of biometrics and its widespread use introduces privacy risks. To mitigate these risks, solutions such as the helper-data system, Pair-Polar Minutiae Structures, fuzzy vault, fuzzy extractors, and cancelable biometrics were introduced, also known as the field of template protection. Fuzzy vault is a practical and promising scheme, which can protect biometric templates and perform secure key management simultaneously. Alignment of the template biometric sample and the query one in the encrypted domain remains a challenging task. In this thesis, we propose an alignment-free cryptosystem based on Pair-Polar Minutiae Structures with multiple fuzzy vaults and minutia local structures. In proposed method, in registration phase, multiple vaults construct for one fingerprint or iris and in verification phase, if at least one of the vaults with respect to its minutiae local structures decoded successfully by the query fingerprint or iris, the secret will be recovered. Experiments on FVC2002-DB2a and FVC2002-DB1a are conducted to show the promising performance of the proposed fingerprint or iris cryptosystem.

Keywords: fuzzy vault, local minutiae structure, alignment-free, pair-polar minutiae structure