Iris recognition in the context of "Facial recognition system"

Biometrics are body measurements and calculations related to human characteristics and features. Biometric authentication (or realistic authentication) is used in computer science as a form of identification and access control. It is also used to identify individuals in groups that are under surveillance.

Biometric identifiers are the distinctive, measurable characteristics used to label and describe individuals. Biometric identifiers are often categorized as physiological characteristics which are related to the shape of the body. Examples include, but are not limited to fingerprint, palm veins, face recognition, DNA, palm print, hand geometry, iris recognition, retina, odor/scent, voice, shape of ears and gait. Behavioral characteristics are related to the pattern of behavior of a person, including but not limited to mouse movement, typing rhythm, gait, signature, voice, and behavioral profiling. Some researchers have coined the term behaviometrics (behavioral biometrics) to describe the latter class of biometrics.

A retinal scan is a biometric technique that uses unique patterns on a person's retina blood vessels. It is not to be confused with other ocular-based technologies: iris recognition, commonly called an "iris scan", and eye vein verification that uses scleral veins.

The human retina is a thin tissue made up of neural cells that is located in the posterior portion of the eye. Because of the complex structure of the capillaries that supply the retina with blood, each person's retina is unique, making retinal scans an emerging authentication method. The network of blood vessels in the retina is not entirely genetically determined and thus even identical twins do not share a similar pattern.

The FIDO (Fast IDentity Online) Alliance is an open industry association launched in February 2013 whose stated mission is to develop and promote authentication standards that "help reduce the world’s over-reliance on passwords". FIDO addresses the lack of interoperability among devices that use strong authentication and reduces the problems users face creating and remembering multiple usernames and passwords.

FIDO supports a full range of authentication technologies, including biometrics such as fingerprint and iris scanners, voice and facial recognition, as well as existing solutions and communications standards, such as Trusted Platform Modules (TPM), USB security tokens, embedded Secure Elements (eSE), smart cards, and near-field communication (NFC). The USB security token device may be used to authenticate using a simple password (e.g. four-digit PIN) or by pressing a button. The specifications emphasize a device-centric model. Authentication over an insecure channel happens using public-key cryptography. The user's device registers the user to a server by registering a public key. To authenticate the user, the device signs a challenge from the server using the private key that it holds. The keys on the device are unlocked by a local user gesture such as a biometric or pressing a button.