End-to-end encryption means that only your own devices hold the key to your data. The company that stores or carries your data keeps a locked copy, and it has no way to open it. On iPhone, some of your data has this protection from the start. Much of it, including your photos and your backups, has it only if you turn on Advanced Data Protection.
Most of us keep our most personal things on a phone: photos of our children, messages with a partner, a scan of a passport, the passwords to our bank. Most of that data does not stay on the phone. It syncs to iCloud, goes into a backup, or passes through a server on its way to another person. Almost every app and service says that it keeps this data "encrypted", and the word sounds reassuring. But it does not answer the question that matters: who else can unlock it?
This guide answers that question in three parts. First, why the place of the key decides who can read your data. Second, which iPhone data is end-to-end encrypted, and how to protect the rest. Third, what end-to-end encryption cannot protect, so you know where the remaining risks are.
Who holds the key decides who can read your data
Encryption turns your data into something that looks like random noise. Only the right key turns it back. The method is rarely the weak point: modern methods such as AES-256 are so strong that no one can break them in practice. The real question is always who has a copy of the key.
With end-to-end encryption, the key is made on your devices and stays there. Your iPhone locks the data before it leaves, the server stores only the locked copy, and your iPad unlocks it when it arrives. The two "ends" are your own devices, or you and the person you send a message to. Nothing in the middle can read it.
A photo on your iPhone
1. Your iPhoneEncrypts the photo with a key that only your devices have.
2. The serverStores the encrypted photo. It has no key, so it cannot read it.
3. Your iPadDownloads the encrypted photo and decrypts it with the same key.
The key never goes to the server. Only the devices at the two ends can read the photo.
If the company keeps a copy of the key, the picture changes. The company can then read your data, and so can anyone who gets into its systems. That includes an attacker after a data breach, an employee who misuses their access, and a government with a court order. The company may have good intentions and strong security. You still depend on both.
"Encrypted" can mean three different things
When an app says "encrypted", it usually means one or more of these. Only the third keeps the company out.
- Encryption in transit protects data while it travels between your device and the server, usually with HTTPS. It stops people on the same Wi-Fi network from reading it. When the data arrives, the server decrypts it.
- Encryption at rest protects data on the server's disks. If someone steals a disk, they cannot read it. But the company holds the key, so its own systems can read your data at any time.
- End-to-end encryption protects data from the moment it leaves your device until it reaches another of your devices. The company never holds the key.
| Protection | End-to-end | At rest | In transit |
|---|---|---|---|
| Safe from people on the same network | Yes | NoOnly with encryption in transit too | Yes |
| Safe if a thief takes the server disks | Yes | Yes | No |
| Safe from the company | Yes | No | No |
| Safe from a legal request to the company | Yes | No | No |
| The company can recover your dataIf you lose your devices or password | No | Yes | Yes |
The last row explains why so many services do not use end-to-end encryption. If the company holds your key, it can help you when you forget your password. If only you hold it, nobody can help you. Many services choose the first, because it lets them help a customer who is locked out. That is a fair choice, but you should know which one they made.
On iPhone, only some data is end-to-end encrypted by default
Apple uses end-to-end encryption for the most sensitive types of data in every iCloud account. For the rest, Apple holds the key unless you turn on Advanced Data Protection. Advanced Data Protection is off by default. Unless you turned it on, Apple holds the keys to your iCloud photos and backups.
End-to-end encrypted for everyone
With the default setting, which Apple calls standard data protection, these types of data are end-to-end encrypted:
- Passwords and the iCloud Keychain, including saved Wi-Fi passwords.
- Health data and Journal entries.
- Home data, payment information and Apple Card transactions.
- Messages in iCloud. There is one gap: your iCloud Backup contains a copy of the key, and Apple holds the key to the backup.
- Screen Time, Siri information and Safari history.
iMessage and FaceTime calls are also end-to-end encrypted between you and the other person.
Not end-to-end encrypted, unless you turn it on
Apple holds the keys to the rest of your iCloud data. This includes your photos and your backups:
- iCloud Photos, with your Hidden album.
- iCloud Backup, which can contain your photo library and the key to your messages.
- iCloud Drive, Notes, Reminders and Voice Memos.
- Safari bookmarks, Wallet passes, Shortcuts and Freeform.
Advanced Data Protection moves all of these to end-to-end encryption. It also closes the gap in Messages, because your backup is then end-to-end encrypted too. iCloud Mail, Contacts and Calendars stay outside, because they must work with the mail and calendar systems of other companies. Apple lists each type of data in its iCloud data security overview.
How to turn on Advanced Data Protection
Before you turn it on, think about recovery. With Advanced Data Protection, Apple can no longer help you if you lose access to your account. Apple asks you to set up a way back in first.
- Set up a recovery method. Add a recovery contact, a person you trust who can help you get back in, or make a recovery key and keep it somewhere safe.
- Update your devices. Each device that uses your Apple Account must run a current version of its software. iOS tells you if a device is too old.
- Turn it on. Open the Settings app, tap your name, then iCloud, then Advanced Data Protection. Tap Turn On Advanced Data Protection and follow the steps.
Advanced Data Protection is not available in all countries. If you do not see the setting, it is not available for your account.
End-to-end encryption protects the journey, not your device
End-to-end encryption is very good at one job: it keeps your data private on servers and on networks. It does nothing once the data is on a device and that device is unlocked. Most real privacy problems happen there, not on a server.
- A person who knows your passcode. When your iPhone is unlocked, your photos and messages are decrypted on the screen. End-to-end encryption does not stop a partner, a family member or a thief who knows your passcode. Read Someone knows your iPhone passcode if that is your concern.
- The other person. When you send a message or a photo, the receiver can save it, take a screenshot or forward it. Encryption protects the delivery, not what happens next.
- Metadata. The service can often still see facts about your data: how large it is, when it changed, and which devices sync it. For messages, it may know who talks to whom, and when.
- A lost key. If you lose all of your devices and your recovery method, your data is gone. This is the price of a key that only you hold. No company can recover it, because no company has it.
How to tell if an app really uses end-to-end encryption
A company that uses end-to-end encryption usually explains it clearly, because it is a strong claim that it wants you to trust. A company that only says "your data is encrypted" usually means encryption in transit and at rest. These signs help you tell the difference:
- The app encrypts data on your device. Look for words such as "on your device" or "before it leaves your device", and a named method, for example AES-256-GCM.
- The company cannot reset your password or recover your data. This sounds like a weakness, but it is the clearest sign of end-to-end encryption. If an email link can reset your password and give you your data back, the company can get to your key.
- The company says what it can still see. An honest design has limits, such as the size of your data or the time of each upload. A company that claims to see "nothing at all" without details has not explained its design.
For photo vault apps, How to choose a photo vault app lists eight questions to ask before you trust one.
End-to-end encryption in DotSafe
DotSafe applies end-to-end encryption to everything that it keeps, and it does not depend on Advanced Data Protection. It encrypts each item on your device with AES-256-GCM before it saves it. The keys come from the pattern that you draw, and DotSafe does not store the pattern anywhere.
With Pro, DotSafe can keep a copy of a vault in your iCloud. iCloud receives only encrypted blocks of one size. Apple cannot read them, and we never receive them. A shared vault works the same way: each member's device has its own key pair, and the owner's device encrypts the vault key for each member. iCloud carries only encrypted keys and encrypted blocks.
DotSafe also reduces metadata. It uploads cover records next to the real ones and pads every block to the same size. As a result, iCloud cannot see how many vaults you have, and it does not see the exact size of each file. How DotSafe encrypts your files explains the full design.
Questions
What does end-to-end encrypted mean?
It means that your data is encrypted on your device, and only the devices at the two ends hold the key. The company that stores or carries the data cannot read it.
Is iCloud end-to-end encrypted?
Partly. Passwords, Health data and some other types are end-to-end encrypted for everyone. Photos, iCloud Drive, Notes and iCloud Backup are end-to-end encrypted only when you turn on Advanced Data Protection.
Can Apple see my photos in iCloud?
With standard data protection, Apple holds the keys to iCloud Photos, so it is able to decrypt them. With Advanced Data Protection on, only your devices hold the keys.
Should I turn on Advanced Data Protection?
If you keep sensitive photos or documents in iCloud, it is worth it. Before you turn it on, set up a recovery contact or a recovery key, because Apple can no longer recover your data for you.
Is end-to-end encryption the same as encryption at rest?
No. With encryption at rest, the company encrypts data on its servers and keeps the key. With end-to-end encryption, the company never has the key.
Can end-to-end encryption be hacked?
Strong methods such as AES-256 have no known practical attack. Attackers go around the encryption instead: they unlock the device, put malware on it, or guess a weak password.
