Protecting Biometric Templates With Sketch: Theory and Practice

Abstract

Abstract-Secure storage of biometric templates has become an increasingly important issue in biometric authentication systems. We study how secure sketch, a recently proposed errortolerant cryptographic primitive, can be applied to protect the templates. We identify several practical issues that are not addressed in the existing theoretical framework, and show the subtleties in evaluating the security of practical systems. We propose a general framework to design and analyze secure sketch for biometric templates, and give a concrete construction for face biometrics as an example. We show that theoretical bounds have their limitations in practical schemes, and the exact security of the system often needs more careful investigations. We further discuss how to use secure sketch in the design of multi-factor authentication systems that allow easy revocation of user credentials.

Secure Sketch for Multiple Secrets

“…Ho et al [8] propose a dual-factor scheme where a user needs to read out a one-time password generated from a token, and both the password and the voice features are used for authentication. Sutcu et al [22] study secure sketch for face features and give an example of how the sketch scheme can be used together with a smartcard to achieve better security.…”

Privacy enhancement of common randomness based authentication: Key rate maximized case

“…The inherent feature of practically all state-of-the-art authentication protocols robust to noise is the storage of some additional information (a.k.a. helper data) assisting in the reliable extraction of a common secret at the enrollment (encoder) and authentication (decoder) sides [1,2,3]. At the same time, since the helper data is somehow input dependent, it raises natural concerns that it should provide little information about the secret extracted from the noisy data (secrecy leak) and input itself (privacy leak).…”

“…The bin index M serves as the helper data and the sequence index S within the bin is the key. The secure sketch approach [3] and Slepian-Wolf based authentication using syndrome coding [2] are exactly based on this architecture. The authentication layer is based on the classical cryptographic authentication as for the noiseless digital inputs.…”

Security enhancement of biometrics, cryptography and data hiding by their combinations

“…For example, as mentioned above, biometrics can be used to protect the key in cryptography, while cryptography and data hiding can be used to protect biometric templates. Noticeable efforts have been made along this line over the past decade [7][27] [4][31] [36]. In this paper, we attempt to present an overview of the state-of-the-art of research in this increasingly important topic by putting biometrics, cryptography and data hiding in the same context of security enhancement.…”