As defined in Computer Security Basics by O'Reilly & Associates, Inc.
Biometrics is the use of a persons unique physiological, behavioral, and morphological characteristics to provide positive personal identification. Biometric systems that are currently avaiable today examine fingerprints, handprints, and retina patterns. Systems that are close to biometrics but are not classified as such are behavioral systems such as voice, signature and keystroke systems. They test patterns of behavior not parts of the body. It seems that in the world of biometrics that the more effective the device, the less willing people will be to accept it. Retina pattern devices are the most reliable but most people hate the idea of a laser shooting into their eye. Yet something such as monitoring keystroke patters people don't mind, but it's not nearly as effective. Biometric verification is forecast to be a multibillion dollar market in this decade. There is no doubt that financial credit and debit cards are going to be the biggest part of the biometric market. There are also many significant niche markets which are growing rapidly. For example, biometric identification cards are being used at a university in Georgia to allow students to get their meals, and in a Maryland day care center to ensure that the right person picks up the right child. In Los Angeles, they are using fingerprints to stop welfare fraud. And they're also being used by frequent business travellers for rapid transit through immigration and customs in Holland, and now at JFK and
Newark airports in the United States. It could also be used to simply prevent one employee from "punching in" for some one else, or to prevent someone from opening up an account at a bank using a false name. Then there is also the security access market, access to computer databases, to premises and a variety of other areas. The Sentry program made by Fingerprint Technologies uses several devices at once.