Apple insists that its Face ID authentication system on the iPhone X should be able to pick out an owner’s face out of a million people without picking up a false positive result. There’s been some worry that that accuracy ratio may have been lowered due to a production issue that needed resolving, but the company has denied this.
What that doesn’t explain is how not just an “evil twin” is able to get Face ID to recognize a face it should not, but non-twin brothers.
— Salavat Khanov (@khanov) November 3, 2017
Rinat Khanov was able to get into his brother Salavat’s iPhone X through a simple Face ID scan, but it took authentication via PIN and several hours of usage.
Another pair of brothers, one of them being Mohanish Sawant on Reddit, also found a similar issue between them and an iPhone X. Between two videos, the Sawants found that it took several passcode unlocks before a second face was finally recognized by Face ID for authentication.
Now, if you have reason to believe that someone knows your PIN, you have a bigger problem on your hands than this. There are several videos out in the media showing how Face ID does pick out one twin sibling from another.
But if there is a case where a similarly-looking surrogate user, like a sibling, uses the device often or if the owner’s face becomes deformed, Face ID is able to create and save a temporary image for unlocking purposes. That data can be dumped once the regular face starts making a more constant appearance.
It’s a quirk some might find a little uneasy, but it all has to come back to that passcode.