Secure sketches for protecting biometric templates

As biometric technologies are becoming pervasive, it is imperative to protect the users of these technologies from misuse of their biometric data. However, unlike user credentials in traditional security systems, such as passwords or tokens, biometric features cannot be consistently sampled, and the matching process can be complex. Furthermore, the consequences of losing biometric data can be far more severe than passwords or tokens. Secure sketches, a recently developed cryptographic primitive, allow noisy data to be restored using some helper-data, while providing bounds on how much sensitive information such helper-data would reveal when obtained by malicious parties. In this chapter, we discuss security threats on the use of biometric templates in security systems, and how secure sketches can be used to address these threats under various circumstances.