[MrDresden]

Android dev here. Still have the same default wallpaper as my Pixel 3 came with 3 years ago.

[refulgentis]

That wallpaper would have the same 3 colors as many, many, other people. The problem here arises when your wallpaper is unique, no?

[Daniel_sk]

You can still use as input along with other parts that are accessible without any permissions - for example the android version, device name, IP address...