A Biometric Signature Scheme with Template Protection and Authenticated Sample Recoverability

Biometric Template Protection (BTP) is an approach to protect biometric data in online biometric authentication. A hopeful scheme for BTP is Biometric Signatures (BSs), which generates a digital signature for a given message using fuzzy biometric data as a private key, utilizing cryptographic tools such as fuzzy extractors. By advancing BTP, we introduce Authenticated Sample Recoverability (ASR), a property that raw biometric samples such as images and videos of biometric traits having captured during past procedures can be recovered from the stored data and a biometric feature generated from the genuine user's sample captured again, while it is difficult to recover the past samples or features only from the stored data. This property is desired in various use cases. For example, in forensics, it is required to post-verify whether the genuine user used the system or fake sample was input during a past specific procedure, because the recovered sample is a strong evidence that the past sample was real or fake. Other examples include investigation of a cause when authentication accuracy in operation is low, and biometric reference update with multi-sample fusion using samples having captured in past procedures. To realize a template protected online biometric authentication system with ASR, we propose Sample Recoverable Biometric Signatures (SRBSs). We present a generic construction of a SRBS scheme with EUF-CMA security, and give a specific construction in the random oracle model.