A Framework for Biometric Visual Cryptography

Visual cryptography is an increasingly popular cryptographic technique which allows for secret sharing and encryption of sensitive data. This method has been extended and applied to secure biometric data in various protocols. Recently, Karabina and Robinson proposed a general framework to help assess the security of these extended biometric visual cryptographic schemes (e-BVC), and formalized the notion of perfect resistance against false authentication [13]. In this paper, we extend the framework in [13] with respect to indistinguishability and index privacy notions. Based on our definitions, we present theoretical analysis of e-BVC schemes and propose new attack strategies. We show that our framework can be applied to derive quantitative security analysis of e-BVC schemes. We discuss the practical impact of our attacks in detail and present several case analysis for a recent implementation of a face recognition protocol by Ross and Othman [21]. In particular, we conclude that the scheme in [21] is not secure with respect to