iOS Internals · iCloud & Your Apple Account · Lesson 2 of 5

iCloud Backup & Advanced Data Protection

See what your iCloud Backup holds and who holds the keys to it.

What's in your backup

You saw in Mobile Networking that standard iCloud Backup isn't end-to-end encrypted unless you turn on Advanced Data Protection. Now let's look closer at what a backup actually holds, and who holds its keys.

iCloud Backup is a copy of your iPhone's data kept on Apple's servers, so you can restore it onto a new or repaired phone. You turn it on in Settings, tap your name, then iCloud, then iCloud Backup. It runs about once a day while your iPhone is charging, on Wi-Fi and locked, and you can tap Back Up Now at any time. Free accounts get 5 GB of storage, which fills up fast.

Apple's rule of thumb is that a backup includes the information and settings on your device that don't already sync to iCloud. That covers:

• device settings and your Home Screen layout
• data from your apps, including apps from other developers
• your texts and iMessages, if Messages in iCloud is off
• your photos and videos, if iCloud Photos is off
• your Apple Watch backup

Things that already sync, such as iCloud Photos or Messages in iCloud, are left out of the backup, because they're stored in iCloud separately.

Now the keys. The default setting is called Standard Data Protection. Your backup is encrypted, but Apple keeps the key in secure hardware in its own data centers. That's how Apple can help you restore your data after you forget your password. The trade-off is that the backup isn't sealed off from Apple itself.

There's one surprise worth knowing. Messages in iCloud is end-to-end encrypted, but if iCloud Backup is also on, the backup contains a copy of the key that protects those messages. Apple does this so you can still recover your messages if you lose your devices. It also means that, without Advanced Data Protection, your messages are only as private as your backup.

Advanced Data Protection

Advanced Data Protection (ADP) is an optional setting, added in iOS 16.2, that puts most of your iCloud data under end-to-end encryption, so only your trusted devices hold the keys.

Some data is end-to-end encrypted for everyone already. Apple lists 15 categories protected by default, including Passwords and Keychain, Health, Journal, Home, payment information, Wi-Fi passwords and Messages in iCloud (with the backup caveat you just met). ADP adds 10 more, for 25 in total: iCloud Backup, iCloud Drive, Photos, Notes, Reminders, Safari Bookmarks, Shortcuts, Voice Memos, Wallet passes and Freeform. iCloud Mail, Contacts and Calendars stay outside it, because they have to work with the world's standard email, contacts and calendar systems.

When you turn ADP on, your device removes the matching keys from Apple's data centers. Apple describes that deletion as immediate, permanent and irrevocable. The upside is that not even Apple can read that data. The downside is that Apple can't help you get it back either. So before ADP will switch on, you must set up at least one recovery method:

• a recovery contact, a trusted person with an Apple device who can give you a code to help you back in, without ever seeing your data
• a recovery key, a 28-character code you write down and keep somewhere safe, away from your phone

The passcode of one of your own devices also works. Lose every one of these and the data is gone for good. ADP also needs all your Apple devices on recent software, and it turns off access to your data on iCloud.com unless you approve it from a trusted device.

One country is a special case. In 2025 Apple said it could no longer offer ADP to new users in the United Kingdom, and that existing UK users would be given time to turn it off themselves. Apple's UK support page, checked in October 2026, still says it can't offer ADP to new UK users. The 15 default categories, iMessage and FaceTime stay end-to-end encrypted there.