Biometric Encryption Chapter from the Encyclopedia of Biometrics

Biometric Encryption (BE) is a group of emerging technologies that securely bind a digital key to a biometric or generate a digital key from the biometric, so that no biometric image or template is stored.What is stored is the BE template otherwise known as a ‘‘bio-metrically encrypted key’’ or ‘‘helper data.’’ As a result, neither the digital key nor the biometric can be retrieved from the stored BE template. BE conceptually differs from other systems that encrypt biometric images or templates using conventional encryption, or store a cryptographic key and release it upon successful biometric authentication. With BE, the digital key is recreated only if the correct biometric sample is presented on verification. The output of BE verification is either a digital key or a failure message. This ‘‘encryption/decryption’’ process is fuzzy because of the natural variabilityof biometric samples. Currently, anyviable BE system requires that biometric-dependent helper data be stored.