SOFT GENERATION OF BIOMETRIC CANDIDATES AND REFERENCES BASED ON EMPIRICAL BIT ERROR PROBABILITY

摘要

A biometric verification device (100) arranged to compare a reference hash (480) with a verification bit string (420) obtained from a biometric, the biometric verification device comprising: —a candidate bit string generator (130) arranged to generate candidate bit strings (430) from the verification bit string and error probabilities, —a hash unit (140) arranged to apply a cryptographic hash function to said generated candidate bit strings to obtain candidate hashes, —a comparison unit (160) arranged to verify if a candidate hash generated by the hash unit matches a reference hash.

主权项

1. A biometric verification device arranged to compare a reference hash with a verification bit string obtained from a biometric,
the biometric verification device having access to error probabilities assigned to bits of the verification bit string, an error probability being indicative of a probability that the bit in the verification bit string corresponding to the error probability differs from a corresponding bit in an enrollment bit string, the enrollment bit string having previously been obtained by a biometric enrollment device from said biometric, the biometric verification device comprising a candidate bit string generator arranged to generate candidate bit strings from the verification bit string and the error probabilities, a hash unit arranged to apply a cryptographic hash function to said generated candidate bit strings to obtain candidate hashes, a reference storage arranged to store at least one reference hash, the at least one reference hash being obtained by the enrollment device from the enrollment bit string and said cryptographic hash function, a comparison unit arranged to verify if a candidate hash generated by the hash unit matches a reference hash stored in the reference storage, wherein the biometric verification device is arranged to obtain biometric verification data from a biometric sensor, the biometric sensor being arranged to measure said biometric, the biometric verification device comprising a quantizer unit arranged to quantize the biometric verification data by mapping at least part of the biometric verification data to a point in a quantization range from a set of quantization ranges, a quantization range in the set of quantization ranges corresponding to a quantization bit string, the biometric verification device being arranged to string together one or more quantization bit strings obtained by the quantizer unit from the biometric verification data to form the verification bit string, wherein the quantizer unit is further arranged to determine a distance between the point in the quantization range onto which the at least part of the biometric verification data is mapped and a closest edge of said quantization range and to assign an error probability to a corresponding bit in the verification bit string.