How your files are protected.
What the encryption does, in plain terms, and where its protection stops.
Last reviewed 11 November 2026.
What is encrypted
Every file is encrypted on your iPhone with AES-256-GCM, a widely reviewed standard, before it is written to storage. File names, folder structure and previews are protected as well. Each file has its own random key, and those keys are protected by keys that belong to the vault.
Where the keys come from
- Your credential. The pattern or passphrase is stretched with PBKDF2 (600,000 iterations), so each guess is expensive.
- Your iPhone. A second key, bound to the device and using the Secure Enclave where the hardware has one, is combined with your credential. Copying the stored files to another machine does not carry that key with it.
- A random vault key. Generated on your device and stored only in wrapped form.
- The recovery phrase. Twelve words encoding 128 bits generated on your device. They can unwrap the vault key without the device-bound key, which is how recovery works on a new iPhone.
One vault does not open another
Each vault has its own keys. There is no master password and no vault list, so one credential never opens more than one vault. How hidden vaults work.
What stays on your iPhone, and what leaves
| Stays on your iPhone | Leaves only if you choose |
|---|---|
| Your files, names and previews, encrypted | An encrypted backup file you save to Files or iCloud Drive |
| Your keys and credential checks | A file you export or share, which is no longer protected by Cipher |
| Everything, with no account and no Cipher server | A purchase, which goes through Apple |
Optional Face ID can open one vault. It is off by default and sits on top of your credential and recovery phrase.
Limits, stated plainly
- No independent audit yet. The design has been reviewed and tested internally, not independently audited. This page will say so when that changes.
- Not unbreakable. Strong encryption does not help if the phone is already unlocked or compromised, or if the credential is easy to guess.
- Exports leave protection behind. A file you save or share out of the vault is an ordinary file.
- Guard the phrase. Anyone with your twelve words and a backup file can open that backup. Keep them apart.
- No credential and no phrase means no recovery. Nobody, including us, can open the vault.
- Deleted is not forensically erased. Flash storage does not guarantee it, and we do not claim it.
- Apple device backups. A backup of your whole iPhone may contain Cipher's encrypted vault files. Without your credential and device key, or the phrase, they cannot be read.
Reporting a security concern
A public security contact will be published here before launch. Until then, please do not send sensitive details through unofficial channels.