Vault9 encrypts everything in your vault on your iPhone before it is stored. The vault opens with your pattern or passphrase and a Secret Key (or Face ID, if you turn it on). Below is what that gives you, then what it does not.
What protects the files
Each file has its own key, and the cipher is AES-256-GCM. If a file is altered or damaged, the app detects it and refuses to show wrong data. The app turns your pattern or passphrase into a key with PBKDF2-HMAC-SHA512 and 600,000 iterations, so each guess costs real work.
The Secret Key is a random 128-bit code that your iPhone makes. It stays in the iPhone Keychain, set to “this device only”. An iPhone backup (iCloud or computer) or a Quick Start transfer does not carry it. A copy of your encrypted vault, the iCloud backup or a copy of the phone’s storage, has no Secret Key in it. To open such a copy, you need the Secret Key and your pattern or passphrase. How the two fit together is on the lock page.
Around the encryption, the app does a few plain things:
- It never stores your pattern or passphrase, not even in a scrambled form.
- It locks when it goes to the background, when you lock it, and after a time without a touch.
- It shows a plain cover with the logo in the app switcher, not your photos.
- It plays large videos from the encrypted file and writes no decrypted copy to storage.
- It has no account and no servers of its own. We never receive your photos or your keys.
Face ID or Touch ID is optional and off by default. Your phone passcode never opens the vault.
What Vault9 cannot do
It cannot protect an open vault. If someone holds your unlocked phone, or malware runs on it, the vault does not help.
It cannot stop a guesser who has your phone. The iPhone holds the Secret Key. iOS makes it hard, but not impossible, to copy it out of the Keychain. From the 5th wrong try in a row, the app makes a guesser wait, up to 60 minutes. It never deletes the vault after wrong tries. So choose a lock that is hard to guess: a pattern of 12 to 15 dots, or better, a passphrase of 4 or more random words.
It cannot reset your lock. There is no recovery key, no reset by email and no support back door. If you forget your pattern and did not write it on your Emergency Kit, the vault is lost.
It has no hidden or decoy vaults. A wrong pattern shows an error, not an empty vault. And no independent security audit has looked at Vault9 yet.
If a kit may have been seen
A kit with your pattern on it opens your vault for anyone who also has a copy of your files. Keep it like a passport. If someone may have seen it, change your pattern or passphrase at once. The Secret Key stays the same, so the vault is then as safe as your new pattern or passphrase. Older copies of the vault still open with the kit and the old pattern or passphrase.
Run the kit test in Settings now and then, and keep your iCloud backup working. It is the only copy of your vault outside the phone.
