How Biometrics Works

Biometric technologies are defined as "automated methods of identifying or authenticating the identity of a living person based on a physical or behavioral characteristic." Unique physical traits, such as fingerprints, iris scans, voiceprints, faces, signatures or the geometry of the hand, can be used. All of those technologies share a methodology involving enrollment and verification. At enrollment, the person offers a "live sample" of the biometric, such as a fingerprint. This is scanned electronically, processed and stored as a template.

To confirm the identity at a future time, the individual presents the live sample, which is matched against the stored template. In a "1:many" search, the individual presents only the live sample, and the database is searched for a match. This is called identification. In a "1:1" search, the user presents a name or personal identification number along with the live sample. The system checks the live sample only against samples stored under that name or PIN. This is called verification or authentication.

Source: DOD Biometrics Management Office