Morton Filters for Iris Template Protection - An Incremental and Superior Approach Over Bloom Filters

Given the need to protect the biometric data increasing due to recent enforcement of GDPR, we address the problem of protected template creation for iris recognition in this work. To this end, we introduce a new Morton Filter Based Template Protection for iris codes. The novel approach relies on creating a multi-bucket based protected template derived from single iris codes. By exploiting the low-rank iris codes from state-of-art iris feature extraction schemes to derive non-noisy iris bits, we design the new framework for creating protected templates by employing Morton Filters. The proposed template protection scheme is further evaluated on constrained and unconstrained iris recognition systems by employing two publicly available databases (IITD Iris and CASIA v4 Distance Dataset). Unlike previous works, to the best of our knowledge, this is the first work to demonstrate the applicability of template protection scheme in an unconstrained setting. The proposed approach achieves a low Equal Error Rate (EER approximate to 0%) on both constrained and unconstrained databases, exemplifying the scalability and adaptability. The approach being antagonistic to various configurations (block size and bit lengths), achieves a high degree of unlinkability deeming it practical for iris recognition systems.