The term biometrics is used either to describe a characteristic or to describe a process. Biometrics generally refers to the anatomical, physiological, or behavioral characteristics used for automated recognition of an individual. Biometric processing systems typically have five components: (1) a sensor to capture and digitize data from individuals; (2) processing algorithms for forming biometric templates; (3) a unit for storing data and templates; (4) matching algorithms for comparing new templates with the stored templates; and (5) a decision process for accepting or rejecting individuals. Three types of errors are used to rank the performance of biometric systems: (1) the failure-to-acquire rate; (2) the false-accept rate; and (3) the false-reject rate. Each of these errors is described followed by a discussion of the five leading biometric technologies: fingerprint readers, iris recognition technology, face recognition technology, hand geometry scanners, and dynamic signature identification systems. Fingerprint readers are used to capture an image of a fingerprint and then mathematically encode the pattern into a template for comparison. An iris recognition system captures the image of an iris with a digital camera. The iris is converted to a template using algorithms and is then compared against all the other iris templates in the database. Face recognition technology uses a camera to capture the image of a face, which is then converted into a template and compared with others in the database. Hand geometry scanners use a charge-coupled device (CCD) camera to capture images of the hand using a plate with guiding pegs and mirrors. The scanner then constructs a template to compare to others in the database. Dynamic signature identification systems use software to measure the speed, direction, and pressure of pen strokes signed on an electronic tablet. The data is then converted into a digital template for comparison with future signatures.