What is FRT?

What is FRT?

Facial recognition technology (FRT) is a biometric method that measures the geometry of a face, such as the spacing of the eyes and the shape of the nose and jaw, and compares the result with a stored template. In IT support you meet it mostly as a sign-in method on laptops and phones, but the same technology is used for door access control and for identifying people in camera footage.

Verification versus identification

• Verification (one-to-one): "Is this the enrolled owner of this device?" This is how Windows Hello face and Face ID work.
• Identification (one-to-many): "Who is this person?" The face is compared against a database of many people, as in surveillance systems.

How device face sign-in works

1. Enrollment: the user's face is scanned and converted into a mathematical template. The device stores the template, not a photo.
2. Capture: at sign-in the camera scans the face again.
3. Comparison: the new scan is compared with the template, and access is granted if the match is close enough.

Spoofing resistance depends on the hardware. Windows Hello face sign-in requires a compatible infrared (IR) camera, which works in low light and is much harder to fool with a printed photo than an ordinary webcam. Apple Face ID uses the TrueDepth camera, which projects infrared dots to build a 3D depth map of the face. Some Android phones offer face unlock with only the regular front camera; that 2D method is easier to spoof, and phones that rely on it often do not allow it for payments or banking apps. Windows Hello and Face ID keep the biometric template on the device rather than on a server.

Face sign-in always has a fallback. Windows Hello requires a PIN before face recognition can be set up, and Face ID requires a device passcode.

Accuracy terms

• False acceptance rate (FAR): how often an impostor is accepted. This is the security risk.
• False rejection rate (FRR): how often the real user is rejected. This is the usability problem.
• Crossover error rate (CER): the point where FAR and FRR are equal; lower is better.

Troubleshooting and privacy

If facial recognition is not offered in Windows sign-in options, check that the device has a Windows Hello compatible IR camera and that its driver is installed and enabled in Device Manager. If recognition fails often, run the Improve recognition option (useful when the user sometimes wears glasses) and check for a dirty lens or a closed privacy shutter. Strong backlighting, masks and major changes in appearance also cause rejections.

Privacy concerns are larger with FRT than with most authentication methods. A face can be captured from a distance without consent, and unlike a password, a compromised biometric cannot be changed. Some jurisdictions regulate how organizations collect and store biometric data, so workplace deployments need clear notice and consent.

FRT on the CompTIA A+ exam

Core 1 objective 1.1 lists biometrics among the physical privacy and security components of mobile devices, and FRT is on the shared acronym list. Core 2 covers facial recognition as an authentication and screen-lock method.

• Facial recognition is a something you are factor. Combined with a different factor, such as a smart card or password, it becomes part of multifactor authentication.
• If a laptop's webcam works but Windows Hello face is not offered, think missing IR camera or driver.
• If a question asks which biometric maps the face in 3D with infrared light, think Face ID or Windows Hello face, not a standard webcam.