AES-256 encryptionProtect by design.
Encrypted on your phone.Every file, its own key.
Hiding a photo isn’t the same as encrypting it. Sigilock seals everything you add with AES-256-GCM before it is written to storage, so what sits on the phone is ciphertext.
Launching soon on iPhone and Android
- key for every file
- 256-bitkey for every file
- authenticated chunks
- 1.5 MiBauthenticated chunks
- copies on a server
- 0copies on a server
How it works
- 01
A key for every file
Each item gets its own random 256-bit key the moment you add it.
- 02
Sealed in chunks
Files are encrypted in 1.5 MiB chunks that can’t be reordered, swapped or cut short without detection.
- 03
Keys locked away
The per-file keys live in an encrypted index that only your sigil or recovery phrase can open.
Hidden is not encrypted
Many ways of hiding photos simply move them somewhere less obvious: a hidden album, a renamed folder, an app with a PIN screen in front of ordinary files. Anyone who gets past that one screen, or reads the phone’s storage directly, sees the photos as they are.
Sigilock encrypts. Every item is turned into ciphertext before it is stored, using AES-256 in GCM mode, the standard behind most modern secure messaging and disk encryption. Without the right key, the stored data is indistinguishable from noise.
Layers of keys
Each photo, video, file and note gets its own random 256-bit key. Those keys are kept in the vault’s index, which is itself encrypted with the vault’s master key. The master key is wrapped twice: once by a key derived from your sigil and your phone’s secret, once by a key derived from your recovery phrase.
This layering is what makes changing your sigil instant, and recovery possible, without re-encrypting every file.
Careful about everything around the files
Encryption is only as good as the copies left lying around. Thumbnails are decrypted into memory only, and the image cache is set never to write them to disk. Videos and documents you open are decrypted to a temporary folder that is wiped every time the vault locks, and at launch. Copies made by the photo picker and the camera are deleted right after encryption.
Tamper-evident
GCM authenticates every chunk, so altered data is detected and rejected.
Nothing cached in the clear
Thumbnails are decrypted in memory only and never written to disk.
Nothing uploaded
Your files are encrypted on the phone and stay on it.
Someone copies the app’s storage off your phone. What they get is ciphertext: without your sigil or recovery phrase, it stays noise.
AES-256 encryption, answered.
More questions? See Support or read how the security design fits together.
Is Sigilock end-to-end encrypted?
There is no other end. Your files are encrypted on your phone and never leave it, so there is no server copy to protect.
Can Sigilock decrypt my photos?
No. We never have your sigil, your recovery phrase or any of your keys.
Does encryption slow the app down?
Sigilock uses your phone’s hardware-accelerated AES, so browsing and viewing stay quick.
What does GCM add to AES?
GCM is an authenticated mode: as well as keeping data secret, it detects any change to the encrypted data, so tampered files are rejected rather than silently opened.
Are file names and album names encrypted too?
Yes. Your item list, file names, album names and notes are all stored in the vault’s encrypted index.
What happens if someone copies my phone’s storage?
They get encrypted data. Guessing their way in would need your sigil plus your phone’s own secret, or your 12-word recovery phrase.
Is AES-256 safe against future computers?
AES-256 is widely considered to keep a comfortable security margin even against the quantum computers researchers anticipate, which is one reason it was chosen.
Works well with
All featuresDraw your first sigil.
Free for 7 days, then €22.99 a year. Your photos stay on your phone, sealed behind a pattern only you know.
Launching soon on iPhone and Android