Biometrics Overview

Key Attributes and Limitations

	The means of identification (or verification) is part of the individual
	Provides the basis for dispensing with conventional personal identification (or verification) methods based upon passwords, tokens, ID cards, and personal identification numbers (PINS).
	Performance determined by a number of factors requiring performance ratings and capabilities to be expressed for products on offer.
	Range of techniques and products emerging to satisfy a wide variety of application needs.
	Costs reducing as more applications are identified and accommodated by available products.
	Performance ratings improving as systems are further developed and experience is gained in their use, including the use of double or more biometrics where two or more biometric feature sets are used for identification (or verification) purposes.
	Biometric templates may be used in conjunction with card-based data carriers (magnetic stripe, smart cards, multi-row bar codes and matrix code data carriers).

Biometric identification encompasses a range of technologies that verify or recognize a person's identity based on unique personal characteristics. It uses a physiological trait, digitally encoded and stored, to accomplish this identification. Biometric systems may simply identify the individual or allow a system to tap into a whole range of "rules" regarding that person. This data may be stored in a variety of formats including smart cards, or in the form of a two-dimensional symbology.

Most biometric systems are used as a means of authentication when a primary means of identification, such as a card, is presented. Other more sophisticated systems are employed for primary identification, requiring no cards, passwords, or PINs. These "automated positive identification" biometric systems prevent multiple enrollments by capturing, recording, and comparing an individual's physical trait against an entire database as opposed to checking one record for a match. The cost and complexity of these types of biometric systems have tended to limit their use to security applications, but as cost comes down, and processing power continues to increase, these systems will see more general use.

For biometric identification, selection of a stable physical characteristic is key. Stable characteristics include the user's hand silhouette, a facial feature, iris pattern, a blood vessel pattern on the retina or hand, and of course, a fingerprint. Individual behaviors may also be used for biometric identification. Behavioral identification may be achieved by analyzing signature dynamics, how one types at a keyboard, or how one speaks (voice patterns). For example, signature dynamics differentiate the parts of the signature that are habitual from those that vary every time you sign your name. Because behavioral characteristics vary over time, behavioral-based equipment may update users' enrolled biometric reference templates each time they access the system. With each use, the machine becomes increasingly proficient at identifying an individual.

Performance of biometric systems is measured by their identifying power, which is calculated using false-rejection and false-acceptance rates. Biometric identification systems allow users to set the desired balance of false-rejection and false-acceptance. If this tolerance is tightened to make it harder for imposters to beat the system, it is also harder for authorized people to access it. Biometric experts state that thorough user training is the best way to reduce false rejections. Knowing and optimizing a system's identifying power, and making sure it is acceptable for your application and in your industry, are critical for system success. For example, adoption of automated signature verification for credit card and check applications has been slow because the financial community demands very low false rejection rates.