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Comment by StringyBob | Hacker News Reader

So - if I followed that correctly the parts you can’t change are the front-camera assembly that includes faceID sensor, and the screen that includes the touch panel (that you use to enter passwords and PINs).

I would assume Apple’s justification is that this is to meet security requirements, particularly given a phone is now commonly used for contactless payments.

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iPhones since the iPhone X have the same repair requirement, however the screen and FaceID are separate so you can continue to use the original.

There's nothing special about the touch panels, the FaceID component is a TPM of sorts.

And the battery as it will report not genuine.

The actual authentication & crypto is happening inside the main SOC. The Face ID sensor is (or should be) just a dumb camera - there's no reason for it to be part of the chain of trust.

Of course there is. That’s how you avoid replay attacks.

Can't you "replay" that data physically by creating a face mask matching the captured data and then presenting it to a legitimate sensor?

IMO the security of the system is that the 3D face data is reasonably secret (you probably can't reconstruct it from a single picture, you'd need pictures from all angles) and the SOC only allows a few attempts before falling back to passcode.

If you have the face data, you don't need to tamper with the hardware, and if you don't have that data then tampering with the sensor won't get you anywhere.

Exactly because you could have a fake camera that could collect your info and make it accessible for an installed app that would upload it for an hostile server. The original camera doesn’t give you access to this data, a counterfeited one possibly could.

That is absurd. What data is to a face, other than its appearance from various angles? That can be obtained from photos of the person.

In that case, why not allow a camera replacement with a factory reset?

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