Biometrics deals with recognition of individuals based on their physiological or behavioral characteristics. The current practice for biometric identification is to use a single mode or multi-mode biometric methods such as: fingerprints, palm prints, face recognition, iris recognition, vein recognition, gait or other bodily characteristics. These methods have significant limitations, including unacceptable False Acceptance Rates and False Rejection Rates. Some of these methods are strongly affected by environmental lighting conditions, others by aging effects, physical conditions, cosmetics, etc. or can be easily fooled or deceived by a substitution. Most of these methods require direct human interaction, which brings additional inconsistencies and errors into the identification process. As an example facial recognition is significantly more complicated because of the size and complexity of human faces. Uncontrolled environmental factors are always associated with facial recognition, such as varying lighting conditions. Additionally, a face may appear at different scales, positions and orientations. Facial expressions significantly differ due to facial hair, make-up, tattoos and glasses. In case of fingerprints, Japanese researchers were able to lift fingerprints from glass and to fool fingerprint scanners using fake fingers made from household ingredients. Iris recognition, based on imaging and analysis of colored protein of the eye, is widely used at border control in countries such as the United States, United Arab Emirates and the United Kingdom, but strongly affected by aging.
With today's e-commerce, information-rich environment, and global computer and information networks, one of the critical needs is to ensure that only authorized individuals gain access to critical devices, restricted or confidential information, or proprietary data. With the availability of ready-to-use “sniffers” and access code (password/PIN) cracking tools, the standard password, passcodes, or PIN combinations are no longer adequate for secure personal identification and authentication. Even sophisticated users of sensitive and proprietary information networks not only fail to change their passwords or PINs, but also assign the same value to all their online access codes. For current and future information networks, it is critical to establish the most reliable security capabilities to establish identity and allow only authorized access to information assets. There is also a need for data integrity, to ensure that no unauthorized changes have been made to the sensitive, private, or restricted information; confidentiality, to restrict information or network access strictly to authorized individual(s); and nonrepudiation, to ensure authorized users do not disavow actual authorized access.
During the last decade, there has been significant demand for development of reliable biometrical authentication for security applications, i.e. verification or identification of a person by using biometrical features. The most commonly used method for authentication is the presentation of a Personal Identification Number (PIN) or a password. Significantly more reliable protection against unauthorized use can be achieved, however, via implementation of biometrical authentication applied as an addition or as an alternative to the knowledge-based authentication methods. Biometric authentication methods have the general advantage over knowledge-based methods in that it is not possible to give the biometric feature to someone else (either intentionally or unintentionally). A password can be given to another person and can be used in the same way as the legal owner, but a biometric feature can only be used by the legal owner. Static biometric features have the critical advantage that they cannot be lost or forgotten because they are always present with a person.
An ideal biometric solution must satisfy many, often competing, criteria. Accuracy is one criterion. A low false acceptance rate (FAR) is crucial to security; it is critical that unauthorized individuals are not misidentified as authorized. The FAR depends on several factors, such as the distinctiveness of the chosen biometric between individuals (essentially, its uniqueness), the ability to capture the biometric information accurately, and the ability to match it correctly. From this point of view, the iris is a good biometric; there is a high degree of randomness and complexity in iris patterns that underpins its uniqueness and distinctiveness between individuals. However, the FAR covers only one side of accuracy. The false rejection rate (FRR—incorrectly rejecting individuals who are actually authorized) also matters. Most currently used or proposed biometric identification methods present a compromise in areas of security, accuracy, practicality or resistance to forgery.