Historically, identity or authentication conventions were based on things one possessed (a key, a passport, or identity credential), or something one knew (a password, the answer to a question, or a PIN.) This possession or knowledge was generally all that was required to confirm identity or confer privileges. However, these conventions could be compromised - as possession of a token or the requisite knowledge by the wrong individual could, and still does, lead to security breaches.

To bind identity more closely to an individual and appropriate authorization, a new identity convention is becoming more prevalent. Based not on what a person has or knows, but instead on what physical characteristics or personal behavior traits they exhibit, these are known as biometrics - measurements of behavioral or physical attributes - how an individual smells, walks, signs their name, or even types on a keyboard, their voice, fingers, facial structure, vein patterns or patterns in the iris.

What is Iris Recognition?
Of all the biometric technologies used for human authentication today, it is generally conceded that iris recognition is the most accurate. Coupling this high confidence authentication with factors like outlier group size, speed, usage/human factors, platform versatility and flexibility for use in identification or verification modes - as well as addressing issues like database size/management and privacy concerns - iris recognition has also shown itself to be exceedingly versatile and suited for large population applications.

The Biology Behind the Technology
Like a snowflake, the iris - the externally visible colored ring around the pupil - of every human eye is absolutely unique, exhibiting a distinctive pattern that forms randomly in utero in a process called chaotic morphogenesis. In fact, it's estimated the chance of two iris (irides) being identical is 1 in 10⁷⁸.

The iris is not the retina - which is found within the eye itself. (Nor should iris recognition be confused with retinal scanning, an older authentication technology based on mapping the vasculature found on this inner part of the eye. Unlike iris recognition, retinal scanning requires the inner eye be subjected to intense illumination, which adds to a general feeling that this older and waning technology is invasive.)

Why Iris Recognition Technology?
There are many reasons why iris recognition is a particularly attractive technology for identity management.

1. Smallest outlier population. There are relatively few people who don't have at least one eye, so there are only a few people who can't use the technology. While blind people can be difficult to enroll, there are instances where blind people have used iris recognition successfully (the technology is pattern-dependent, not sight dependent).
2. Unparalleled Stability. The patterns in the human iris are fixed from about one year in age and remain constant (barring trauma, certain rare diseases, or change that may occasionally ensue from some ophthalmologic surgical procedures.) This means that once a subject is enrolled, the need to re-enroll is lower than for other biometric identification options, where changes in voice timbre, weight, hairstyle, finger or hand size, where sustained manual labor or the presence of a superficial cut can require re-enrollment.
3. Unique Design Facilitates Superior Management of Large Databases. Iris recognition is the only biometric authentication technology designed to work in the 1-n or exhaustive search mode. This makes it ideal for handling applications that require management of large user groups, such as a National Documentation application might necessitate. The technology is ideally suited to handle large databases, and does so without any degradation in accuracy.   Iris Access platforms integrate well with large database back ends like Microsoft® SQL and Oracle® 8 & 9i.
4. Unmatched Search Speed in the one to many search mode is unmatched by any other technology, and is limited not by database size, but by hardware selected for server management. In a UK Government-commissioned study,  Iris Access platform searched records nearly 20 times faster than the next fastest technology. Iris recognition technology platforms and solutions enabled by  are ideal for applications requiring high throughput speed.
5. Application Mode Versatility. While the technology was initially designed to work in one-to-many search mode, iris recognition is perfectly suited to applications that require 1-1 matching, or verification mode operation. This makes iris authentication ideal for use in upgrading security systems that have a large base of installed card readers or PIN pads. Compatibility with the Weigand environment means that a high integrity security overlay can be built in to such systems by adding Iris Access 3000 to a prox card station. Or, in instances where legislative or strategic considerations demand it, the technology is ideally suited for smartcard use, leaving the issue of biometric database management a moot one, as the user retains control of biometric data - in this case a 512-byte template held on the smartcard.
6. High-level User Acceptance. Most people in the developed world are comfortable with the idea of having their picture taken, particularly if there is some benefit to having it done. Iris recognition involves nothing more than taking a digital picture of the iris (from moving video), and recreating an encrypted digital template of that pattern. That 512-byte template cannot be re-engineered or reconstituted to produce any sort of visual image, and provides a high level defense against identity theft, a rapidly growing crime. There are no lasers or bright lights involved in iris recognition and authentication is entirely non-contact. Enrollment is opt-in, and data collected bears no resemblance to that collected for any purpose other than real-time human authentication, so the technology is free of any surveillance-related or criminal/forensic stigmas.
7. Convenient Intuitive User Interface: Using the technology is an almost intuitive experience. Proximity sensors activate the equipment, which includes mirror-assisted alignment functionality. Audio auto-positioning prompts, auto-focus image capture, and visual and audio authentication decision cueing complete the process.