In an interview on Friday, Apple’s SVP of Software Engineering Craig Federighi answered a few questions about the Face ID feature that will ship out to customers in November with the iPhone X.
Federighi spoke with TechCrunch to clear up some questions and concerns about Apple’s biometric authentication solution that have cropped up in the days following its debut.
Starting with Face ID’s data backbone, Federighi said Apple collected a “quite exhaustive” library of face scans from consenting subjects that was subsequently used to train the system. To maximize accuracy, Apple captured high quality depth maps of each person’s face from various angles. Federighi said:
“Phil mentioned that we’d gathered a billion images and that we’d done data gathering around the globe to make sure that we had broad geographic and ethnic data sets. Both for testing and validation for great recognition rates. That wasn’t just something you could go pull off the internet.”
He goes on to say that Apple is holding on to the high fidelity depth map data for further algorithm training, noting the dataset is needed for system optimization. That being said, he stressed that Apple’s facial scanning library is protected and all user data is kept secure.
“We do not gather customer data when you enroll in Face ID, it stays on your device, we do not send it to the cloud for training data.”
Just like Touch ID, Apple does not retain Face ID data, that information lives in the iPhone X Secure Enclave. Also like Touch ID, raw Face ID image data is processed and stored as a mathematical model that cannot be reverse engineered back into model of the user’s face. The executive notes iPhone X boasts a redesigned Secure Enclave capable of performing the re-training procedures that power Face ID’s adaptive features.
Face ID is able to adapt to changes in a user’s face. For example, the system will work when a user grows a beard, wears a hat or puts on glasses. However, the report notes that Face ID will be unable to recognize a user whose face is obscured by a mask or niqab. In such cases, Apple is recommending that users enter a passcode.
Here are a few more additional details worth noting:
- If you haven’t used Face ID in 48 hours, or if you’ve just rebooted, it will ask for a passcode.
- If there are 5 failed attempts to Face ID, it will default back to passcode.
- Developers do not have access to raw sensor data from the Face ID array. Instead, they’re given a depth map they can use for applications like the Snap face filters shown onstage.
- You’ll also get a passcode request if you haven’t unlocked the phone using a passcode or at all in 6.5 days and if Face ID hasn’t unlocked it in 4 hours.
Federighi earlier this week noted users can manually disable Face ID by gripping iPhone X’s side buttons, a feature that could come in handy when a user is forced to hand over the device unwillingly. He said:
“So, if you were in a case where the thief was asking to hand over your phone — you can just reach into your pocket, squeeze it, and it will disable Face ID. It will do the same thing on iPhone 8 to disable Touch ID.”
Finally, Federighi said Apple intends to release a white paper on Face ID for security researchers and other interested in learning more about the cutting-edge facial recognition technology.