"Biometric" comes from the Greek words "bio" (life) and "metric" (to measure). Biometrics are technologies used for measuring and analyzing a person's unique characteristics. There are two types of biometrics: behavioral and physical. Behavioral biometrics are generally used for verification while physical biometrics can be used for either identification or verification.
What are biometric systems used for?
Biometrics are used for identification and verification:
Identification is determining who a person is. It involves trying to find a match for a person's biometric data in a database containing records of people and that characteristic. This method requires time and a large amount of processing power, especially if the database is very large.
Verification is determining if a person is who they say they are. It involves comparing a user's biometric data to the previously recorded data for that person to ensure that this is the same person. This method requires less processing power and time, and is used for access control (to buildings or data).
What are the main types of biometric systems?
The main physical biometric technologies include:
There are also a number of behavioral biometric technologies such as voice recognition (analyzing a speaker's vocal behavior), keystroke (measuring the time spacing of typed words), gait recognition (manner of walking), or signature (analyzing the way you sign).
Other biometric techniques, still in exploratory stages would include DNA biometrics, ear shape, fingernails or odor.