Biometrics are measured human physical and behavioral characteristics that can be used for the purpose of personal identification (associating an identity with a person)     . A traditional example is the fingerprint. Fingerprints are widely recognized as being unique to each person and are a permanent physical characteristic (biometric). Because of this, fingerprints have been used for personal identification for many years.
A biometric personal identification system measures some physical and/or behavioral characteristic of a user and compares the measured information with previously stored information for the purpose of identifying the user.
When using a typical ATM (automated teller machine), an ATM card and a PIN (personal identification number) are required for someone to access their bank account. When paying for goods at a department store, a credit card and a signature are all that is required. When buying gasoline, only a credit card is necessary. These are examples of automated personal identification. However, one should understand that only the cards, signatures, and/or PINs are what is actually identified, not the person who provided them. They could have been provided by anyone. The purpose of using biometrics is to provide a means of absolute identification for a given task. These tasks can include bank transactions, facility or computer access, and consumer purchases. The use of biometrics allows for positive personal identification without reliance on items that can be lost, forged, forgotten, or stolen. Common biometrics includes fingerprints, hand geometry, facial features, speech pattern, iris characteristics, and retinal features. Items associated with personal identification that can be lost, forged, forgotten, or stolen include keys, ATM cards, credit cards, debit cards, driver's licenses, PINs, safe combinations, passwords, and signatures. An identification system that uses biometrics offers accurate personal identification and the added luxury of not having to keep up with cards and tokens or relying on recollection of PINs, passwords, or combinations
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