features may not have fully developed. If you're concerned about this, we
recommend using a passcode to authenticate.
Face ID security
Face ID is designed to confirm user attention, provide robust authentication !
with a low false match rate, and mitigate both digital and physical spoofing.
The TrueDepth camera automatically looks for your face when you wake !
iPhone X by raising it or tapping the screen, as well as when iPhone X attempts
to authenticate you to display an incoming notification or when a supported app
requests Face ID authentication. When a face is detected, Face ID confirms
attention and intent to unlock by detecting that your eyes are open and directed
at your device; for accessibility, this is disabled when VoiceOver is activated or
can be disabled separately, if required.
Once it confirms the presence of an attentive face, the TrueDepth camera
projects and reads over 30,000 infrared dots to form a depth map of the face,
along with a 2D infrared image. This data is used to create a sequence of 2D
images and depth maps, which are digitally signed and sent to the Secure
Enclave. To counter both digital and physical spoofs, the TrueDepth camera
randomizes the sequence of 2D images and depth map captures, and projects !
a device-specific random pattern. A portion of the A11 Bionic processor’s neural
engine—protected within the Secure Enclave—transforms this data into a
mathematical representation and compares that representation to the enrolled
facial data. This enrolled facial data is itself a mathematical representation of
your face captured across a variety of poses.
Facial matching is performed within the secure enclave using neural networks
trained specifically for that purpose. We developed the facial matching neural
networks using over a billion images, including IR and depth images collected in
studies conducted with the participants’ informed consent. We worked with
participants from around the world to include a representative group of people
accounting for gender, age, ethnicity, and other factors. We augmented the
studies as needed to provide a high degree of accuracy for a diverse range of
users. Face ID is designed to work with hats, scarves, glasses, contact lenses,
and many sunglasses. Furthermore, it's designed to work indoors, outdoors, and
even in total darkness. An additional neural network that’s trained to spot and
resist spoofing defends against attempts to unlock your phone with photos or
masks.
Face ID data, including mathematical representations of your face, is encrypted
and only available to the Secure Enclave. This data never leaves the device. It is
not sent to Apple, nor is it included in device backups. The following Face ID
data is saved, encrypted only for use by the Secure Enclave, during normal
operation:
•
The mathematical representations of your face calculated during enrollment.