The short version
- Stesh is fully offline. No data ever leaves your device.
- We collect no personal information, analytics, or usage data.
- We have no servers, no accounts, and no cloud storage.
- Your images and messages are processed entirely on-device.
- The only thing stored outside of your gallery is a small scan cache in app storage, which you can clear at any time from Settings.
1. Who we are
Stesh is an Android application developed by Knowledge Channels Technologies. The app encodes and decodes secret text messages hidden inside PNG images using steganography and AES-256 encryption. It operates entirely offline.
2. Information we collect
We collect nothing. Stesh does not collect, transmit, store remotely, or share any personal data, usage statistics, crash reports, analytics, or any other information about you or your device.
There are no third-party SDKs, advertising frameworks, or analytics libraries included in the app.
3. What stays on your device
All data generated by Stesh is stored locally on your device only:
Gallery images
Encoded images are saved to your device's Pictures/ folder via Android's MediaStore API. These are standard PNG files. Stesh does not upload, back up, or transmit them anywhere.
Scan cache
To avoid re-scanning your gallery on every launch, Stesh stores a small cache of scan results (URI, last-modified timestamp, whether a secret was detected) in Android's SharedPreferences under the app's private storage. This cache contains no message content — only metadata about which images have been scanned. It can be cleared at any time from Settings → Developer → Clear Cache.
User preferences
Two settings are persisted locally: whether the biometric vault lock is enabled, and whether encoding replaces images in-place. These are stored in app-private SharedPreferences and never leave the device.
Shared files
When you share a .stsh file, Stesh writes a temporary copy to the app's cache directory and passes it to the Android share sheet. The temporary file is managed by the OS and is not transmitted by Stesh.
4. Permissions
Stesh requests the following Android permissions:
| Permission | Why it's needed |
|---|---|
| READ_MEDIA_IMAGES | Read images from your gallery to encode or decode secrets. Required on Android 13+. |
| READ_EXTERNAL_STORAGE | Read gallery images on Android 12 and below. |
| WRITE_EXTERNAL_STORAGE | Save encoded images to your gallery on Android 9 and below. |
| CAMERA | Take a new photo directly from the app to encode a secret into it immediately. |
| USE_BIOMETRIC | Authenticate with fingerprint or face unlock before opening the Vault. Biometric data is handled entirely by the Android system — Stesh never sees it. |
| READ_MEDIA_VISUAL_USER_SELECTED | Support Android 14's partial photo access model. |
No permission is used for any purpose other than what is described above.
5. Biometric data
Stesh uses Android's BiometricPrompt API to protect access to the Vault. Biometric authentication is performed entirely by the Android operating system. Stesh never accesses, processes, or stores any biometric data such as fingerprints or facial geometry.
6. Encryption
All messages encoded by Stesh are encrypted with AES-256-CBC before being written into image pixels. Encryption keys are derived on-device from image content and, optionally, a user-supplied password. No encryption keys are stored, transmitted, or recoverable by us.
We have no technical ability to decrypt your messages. If you lose your password, the message cannot be recovered.
7. Children's privacy
Stesh does not knowingly collect any information from anyone, including children under 13. As no data is collected at all, there is nothing to distinguish.
8. Changes to this policy
If we ever change how Stesh handles data — for example, if a future version adds optional crash reporting — this policy will be updated with a new effective date and a clear description of what changed. The updated policy will be available before the updated app version is published.
Given the offline-only nature of the app, we do not anticipate material changes.
9. Contact
If you have questions about this privacy policy or how Stesh works, you can reach us at: