In this example, though, the iPhone did not fall for the 3D printed head, so this attack would likely be just as effective with a picture.

Just as ineffective

I meant against the Android phones, which are just using a 2D camera for face detection.

I can imagine it requires the head to move like a real head.

Not lasers, it’s an infrared dot pattern. Projected on a surface and the distortions are viewed with an infrared camera and analyzed for depth.

Actually it might be possible to hack if your screen could output IR wavelengths.

iPhone uses VCSEL lasers operating in the infrared [1].

[1] http://spie.org/newsroom/faces-light-up-over-vcsel-prospects...

Wow, thanks for that. An infrared laser, I stand corrected.

>To detect whether there is something in front of the iPhone X, it is believed that the phone uses a "time-of-flight" (TOF) sensor, powered by an LED-based infrared illuminator... If the TOF sensor detects an object, it triggers the iPhone X's True Depth camera to take a picture. If that reveals a face, the phone activates its dot projector, shining a single infrared VCSEL through an optical system to create 30,000 spots while its infrared camera captures an image. It sends both regular and spottily illuminated IR face images to an application-processing unit (APU) that can recognize the owner and therefore unlock the phone.