A Framework for Iris Biometrics Protection: A Marriage Between Watermarking and Visual Cryptography

This paper presents a novel security architecture for protecting the integrity of iris images and templates using watermarking and visual cryptography (VC). The proposed scheme offers a complete protection framework for the iris biometrics which consists of two stages: the first stage is for iris image protection, while the second is for the iris template. First, for protecting the iris image, a watermark text which carries personal information is embedded in the middle band frequency region of the iris image using a novel watermarking algorithm that randomly interchanges multiple middle band pairs of the discrete cosine transform. Second, for iris template protection, the binary iris template is divided into two shares using VC, where one share is stored in the database and the other is kept with the user on a smart card. In addition, the SHA-2 hash function is utilized to maintain the integrity of the stored iris template in both the database and smart card. The experimental and comparison results on the CASIA V4 and UBIRIS V1 iris databases demonstrate that the proposed framework preserves the privacy of the iris images and templates and retains robustness to malicious attacks, while it does not have a discernible effect on the recognition performance.