Biometric systems use automated techniques for identifying individuals by their unique physical characteristics. Fingerprints, hand geometry, iris and retina patterns and facial features can all be used. Other recognition systems in limited use or under development are based on vein patterns on the back of a clenched fist, the chemical make-up of body odor, the sound of the voice and DNA. All biometric systems include four basic steps: (1) biometric characteristics are captured during an enrollment process; (2) any unique features are extracted and converted into a mathematical code that is stored as a biometric template for a particular person; (3) when a person' identity is checked for recognition and verification, another biometric sample is taken and compared against the template; and (4) if the template and the new sample match, approval or access is granted. Figures