Biometric Technology: What Is It?

The textbook definition of biometric technology is: "automated methods of verifying or recognizing the identity of a living person based on a physiological or behavioral characteristic." To further understand biometric technology let's define some of the terms in the definition. "Automated methods" refers to the three basic methods used in biometric systems: 1) a mechanism to scan and capture a digital or analog image of an intrinsic human characteristic; 2) compression, processing, and comparison of the scanned image to a database of stored images; & 3) an interface with applications systems.

Upon hearing about biometric technology, a natural first question many people ask centers around fooling the system with fake fingers, recordings of voices, plaster hands, etc. Biometric technology has advanced to a point that it can measure things such as body temperature and blood flow to ensure the biometric being scanned is indeed from a living person so these attempts at trickery are thwarted.

Physical Biometrics vs. Behavioral Biometrics

Biometrics are human characteristics but they can be either physical or behavioral so let's distinguish between the two. Physical characteristics are things such as fingerprints, handprints, or eye characteristics that can be acquired buy a retinal scan. On the other hand behavioral characteristics are things like keystroke dynamics which are your typing patterns at a keyboard and the unique characteristics of an individual's voice.

Biometric Testing

The accuracy of biometric systems is measured by their False Rejection Rate (FRR) and their False Acceptance Rate (FAR). Most biometric devices have sensitivity settings that can be set to make it more difficult for impostors to gain unauthorized access. There are trade offs however. If the settings are set to make it more difficult for unauthorized individuals to gain access, it will also be more difficult for authorized individuals to gain access. As the FAR decreases, the FRR increases. It follows that if the system is set to allow easier access for authorized personnel, it will also be easier for unauthorized individuals to slip through. Think of it in terms of a car alarm. If the car alarm is very sensitive, the chances of theft are decreased but the chances of you accidentally setting off the alarm are increased. So you must select a setting where you're comfortable that the alarm will prevent theft while not constantly going off in false alarms. The same holds true for the owner of the biometric system.

There has been some confusion as to the meaning of "false accept" and "false reject". Depending on the whether a positive or negative identification biometric system is being used, the terms could have opposite meanings. In an effort to clear up any potential confusion, the U.S. National Biometric Test Center is now promoting the terms "false match" and "false non-match" as the standard industry-wide terminology to be used in measuring the effectiveness of biometry systems.