Pixel 6 under-display fingerprint scanner seen in Android 12
Stock Android hasn't always kept up with the trends and development in biometric security. Fingerprint remains its strongest supported system and even then it only supports the traditional optical sensors on the back of phones or under power buttons. Face recognition is still the same crude one from years ago and not the hi-tech radar-based implementation that the Pixel 4 flaunted two years ago. Now it seems that Google is finally embracing the now-common under-display fingerprint scanning technology in Android 12 but it might also be exclusive to what will eventually become the Pixel 6.
Given how many smartphones there are with in-display fingerprint scanners, some might be surprised to hear that Android itself, at least the "pure" Android that comes from Google, doesn't actually support the technology. In a nutshell, this means that each OEM rolls out their own proprietary implementation and that Custom ROMs that base their code on the Android Open Source Project or AOSP don't have any such access.
The latest developer previews for Android 12 hinted that Udfps, short for "Under-display fingerprint scanner" is coming to the latest version of Google's mobile platform. Back in the first dev preview, it wasn't clear whether this would be available to AOSP or a Pixel exclusive. With DP2, however, XDA spotted hints that this feature is instead intended "com.google.android.systemui", meaning it is specifically for a Pixel phone only.
The switch to using a fingerprint scanner comes at a time when facial recognition technologies on phones are unable to cope with people wearing face masks for protection. It's still puzzling that Google took this long to finally add support for these under-display sensors but, then again, it has always been slow to jump on trends anyway. That is unless it creates its own, like the Soli-based facial recognition on the Pixel 4.
That said, this implementation does have one drawback, at least for third-party ROM makers and perhaps other OEMs. It still isn't generic support for the technology that all Android developers will be able to hook into, leaving them to still rely on different implementations for now.