Inserting Chaff Minutiae for the Geometric Hashing-based Fuzzy Fingerprint Vault

Recently, a cryptographic construct, called fuzzy vault, has been proposed for cryptobiometric systems, and some implementations for fingerprint have been reported to protect the stored fingerprint template by hiding the fingerprint features. Also, solutions to the most challenging issue in applying the fuzzy vault to fingerprint have been proposed. One of the solutions exploits the idea of the geometric hashing to solve the auto-alignment problem. In this paper, we analyze the feature distribution of the generated hash table as a stored fingerprint template and improve the security of the geometric hashingbased fuzzy vault by uniformly distributing the features in the stored fingerprint template. That is, after analyzing the geometric transform from the real and chaff minutiae in the fingerprint image to the generated hash table, we modify the way to add the chaff minutiae. The goals of this addition make the feature distribution of the hash table for the chaff minutiae similar to that of the real minutiae as well as the feature distribution of the fingerprint image for both types of minutiae uniform. Based on the experimental results, we confirm that the proposed approach can perform the fingerprint verification more securely without a significant degradation of the verification accuracy.