Secret Key Generation from a Biometric Source with an Eavesdropping Jammer

We consider secret key generation from a biometric source. We examine an information theoretic model where a legitimate user reads from the biometric source two times. A secret key is generated from the first output of the biometric source. From the second output of the biometric source this secret key is reconstructed. The corresponding outputs of the biometric source are modelled as jointly distributed random variables. We also assume that a helper message, generated after reading from the biometric source for the first time, is available to the legitimate user when reading from the biometric source for the second time. Additionally the helper message is assumed to be publicly available and an eavesdropper wants to learn the secret key from the helper message. We assume the biometric source is jammed before the legitimate user reads from the source for the second time. The jammer gets to know the public helper message too. Considering the secret key generation rate and the privacy leakage rate we characterize the corresponding capacity region taking into account protocols that guarantee perfect secrecy and uniform distribution of the key.