Automated biometrics-based personal identification.

Biometrics-based personal identification attempts to answer the questions ‘‘Who are you?’’ and ‘‘Are you who you claim to be?’’ Personal identification, regardless of method, is ubiquitous in our daily lives. For example, we often have to prove our identity to gain access to a bank account, to enter a protected site, to draw cash from an ATM, to log in to a computer, to claim welfare benefits, to cross national borders, and so on. Conventionally, we identify ourselves and gain access by physically carrying passports, keys, badges, tokens, and access cards or by remembering passwords, secret codes, and personal identification numbers (PINs). Unfortunately, passports, keys, badges, tokens, and access cards can be lost, duplicated, stolen, or forgotten; and passwords, secret codes, and PINs can easily be forgotten, compromised, shared, or observed. Such loopholes or deficiencies of conventional personal identification techniques have caused major problems to all concerned. For example, hackers often disrupt computer networks; credit card fraud is estimated at $2 billion per year worldwide; and in the USA, welfare fraud (by double dippers) is believed to be in excess of $4 billion a year. Robust, reliable, and foolproof personal identification solutions must be sought to address the deficiencies of conventional techniques. Right at the frontier of such solutions is biometrics-based personal identification. What are biometrics? Biometrics are personal physical or biological measurements about an individual. Some frequently used measurements are height, weight, hair color, eye color, and skin color of an individual. As one may easily observe that these particular measurements can give a ‘‘correct’’ description about an individual, but more than one individual can fit such a description. To uniquely identify an individual based on biometrics data, the following characteristics of biometrics data are desirable: highly unique to each individual, easily obtainable, time-invariant (no significant changes over a period of time), easily transmittable, able to be acquired as nonintrusively as possible, and distinguishable by humans without much special training. The last characteristic above is helpful to manual intervention, when deemed necessary, after an automated biometrics-based identificationyverification system made a decision. Automated biometrics-based personal identification systems can be classified into two main categories: identification and verification. In a process of verification (1-to-1 comparison), the biometrics information of an individual, who claims certain identity, is compared with the biometrics on the record that represent the identity that this individual claims. The comparison result determines whether the identity claims shall be accepted or rejected. On the other hand, it is often desirable to be able to discover the origin of certain biometrics information to prove or disprove the association of that information with a certain individual. This process is commonly known as identification (1-to-many comparison).