> If a user of the app deletes, it completely nukes their entire account, down to the last byte. Edit: This comment is in response to the suggestion that all a

> If a user of the app deletes, it completely nukes their entire account, down to the last byte. Edit: This comment is in response to the suggestion that all apple apps delete all local data which after rereading the parent they were only suggesting for their app. Are you sure about that? I'm not an iOS developer but as a user I noticed a few years ago that deleting google apps, even all google apps, off my phone and from icloud still resulted in a freshly installed google app suggesting I log in using the account I was last using. My best guess after doing some searching is re-identification was done using a "Keychain Access Group"[1] which does not automatically get deleted on app uninstall. Though it is stated [2][3] that this is an implementation detail and not a guaranteed behavior. If I recall correctly the only way to reset the Keychain Access Group if the app doesn't do it is to wipe the phone. It is also possible to persist data if an app is part of an "Application Group" and one of the apps in that group is still installed on your device then data shared via that approach will not be automatically deleted unless all apps in that group are uninstalled (from what I have read). Apple does have the "DeviceCheck"[4] framework which significantly limits the amount of bits which can persist across app reinstalls which prevents / severely limits an app's ability to reidentify users but still enable some useful use cases. However until "Keychain Access Group" persistence is removed there is not a lot motivating a developer to use this framework. 1: https://developer.apple.com/documentation/security/keychain_services/keychain_items/sharing_access_to_keychain_items_among_a_collection_of_apps https://developer.apple.com/documentation/security/keychain_... 2: https://developer.apple.com/forums/thread/36442?page=2 https://developer.apple.com/forums/thread/36442?page=2 and for some prior history see https://developer.apple.com/forums/thread/72271?page=2 https://developer.apple.com/forums/thread/72271?page=2 3: https://stackoverflow.com/questions/60485419/ios-keychain-data-will-persist-after-app-deleted-and-reinstall https://stackoverflow.com/questions/60485419/ios-keychain-da... 4: https://developer.apple.com/documentation/devicecheck https://developer.apple.com/documentation/devicecheck