Hacker News Reader

>If you backup your iPhone, apps and their data don't actually get backed up. Instead, your computer just stores a list of the apps installed and where the icons were, and app data only gets backed up if the developers have used special APIs or whatever to opt-in to having the app's data be part of the backup process.

Not at all true [1].

Everything in the app's container gets backed up with the exception of the app bundle, Library/Caches/, tmp/, and other things the developer explicitly opted out.

[1] https://developer.apple.com/icloud/documentation/data-storag...

Fair enough. But regardless, Apple is describing it as performing a full backup, when in reality there is no way to restore your phone to its previous state.

It doesn't matter how the phone works or how the apps work. If you can't restore, you don't have a backup. End of story.

Google Authenticator almost certainly doesn't store its TOTP state on the filesystem - it is in the secure enclave. I don't use Authenticator so I can't guess whether they marked its state as exportable.

If Google Authenticator codes aren't restored, then I'm guessing you're restoring to another device. Google Authenticator presumably uses the keychain, and for keychain items, unless the item has opted-in to iCloud syncing, the keychain item can only be restored to the device that created it. Which is to say, there's two distinct chunks of keychain data. There's the local-only items, and the iCloud-synced items. The local-only items use a secret known to the device when encrypting, so they cannot be decrypted anywhere else. iCloud-synced items are of course encrypted in a manner that allows them to be decrypted on another device (otherwise syncing wouldn't work).

tl;dr: If you restore your encrypted backup to the phone that created it, you get your full keychain back. If you restore it to another phone, you only get keychain items that opted in to iCloud syncing.

Just a note, this is incorrect.

Did you restore a iOS backup to a different device then the backup was originally created on?

The way that sensitive data is encrypted on iOS (when the proper API's are used), certain types of data can be marked to be only able to be decrypted on the same device. That is, if a backup is restored to a different device, the unique device ID will have changed, and some encrypted items will not be able to be decrypted.

This is intentional. More details at https://www.apple.com/business/docs/iOS_Security_Guide.pdf

> Did you restore a iOS backup to a different device then the backup was originally created on?

Yes, I had my phone replaced. And if it's intentional that it's supposed to work that way, then Apple shouldn't tell people that they have a full backup and are good to go when that isn't actually the case.

Especially since it makes zero sense for it to even work that way. If the backup is encrypted on your computer, then it should make zero difference whether the phone itself is different.

Regardless though, how it works and why it works the way it does is irrelevant. The issue is with Apple telling users that they have a backup when in fact they do not.

This is a discussion of backup/restore using APFS snapshots on macOS (Sierra and High Sierra).

You appear to be talking about iOS.

Not. The. Same. OS.

It is actually largely the same OS, they just call it different things depending on what device it's on. And there is zero reason to believe that Apple isn't currently doing the same thing on MacOS, or won't do so without warning in the future.

Shockingly incorrect. From the kernel, to the BSD subsystem, to the graphics layer, these are all dramatically different things between the two operating systems.

Part of APFS is getting the iOS and macOS filesystems back in line. HFS+ started to diverge between the two of them.

> It also means that if an app is no longer in the app store, there is no way to get that app back even if it would otherwise still work on your phone.

This is what I hate since iOS 10 and the removal of app sync in iTunes (and with the latest iTunes, apps are completely out without any alternatives). I've avoided upgrading iTunes as well as macOS for this reason. I don't want to sacrifice convenience and waste time spending hours re-downloading all apps from the App Store when I could get it a lot more quickly from a local copy. Apple just doesn't seem willing to recognize how bad connectivity is in most places around the world.

I wait in the hope that Apple will bring out some kind of "Sync" app that's separate from iTunes but works with it to easily backup apps as well as data on computers for quicker restores.

I recently had to wipe and reinstall my phone from an iCloud backup, and my Google Authenticator configurations were restored as well.

Correct, the keysbags are setup so that they will decrypt when restored to the same device where the backup was taken.

The other poster has a fair point to be upset, it's not at all obvious to a consumer why Google Authenticator would not restore a backup properly to a new device.

Is it really Apple's doing, or Google's, in this case? Google Authenticator is the one specifying that the hardware must match in order to decrypt, after all...

That behavior is why I recommend against Google Authenticator. Restoring a backup should restore all data, period.