Three factor scheme for biometric-based cryptographic key regeneration using iris

In this paper we propose a three factor (smart card, iris code and password) scheme for cryptographic key regeneration based on fuzzy sketches idea which handles biometric variability with error correcting codes. Because errors in iris codes have mixed nature (random and burst errors), concatenated Hadamard and Reed-Solomon codes are used in this work. Hadamard codes can correct up to 25% errors but experiments showed that it is necessary to increase this capacity. In order to correct this higher amount of errors, a zero padding scheme is introduced. In addition, a user specific iris code shuffling key is used which increases the separation between genuine and impostor Hamming distance distributions, providing better separability between genuine users and impostors. We succeeded in regenerating a 198-bit key with estimated entropy of 83 bits on the NIST-ICE database at 0.055% False Acceptance Rate (FAR) and 1.04% False Rejection Rate (FRR).