Editor's Overview
Oversec is a text encryption application developed by oversec, packaged as a single Android APK of version 1.5 weighing in at 5.26 MB. The package targets Android 4.1+ and above. Below you'll find the publisher's own description, a quick spec sheet, and a short buyer-beware checklist so you know exactly what you're installing before tapping download.
Install Checklist
- Only download through the button on this page — never from third-party mirrors or shortened links, which are the most common way malware spreads.
- File size is a light 5.26 MB, so it installs quickly even on modest connections.
- This build is signed by "oversec" — always verify the developer name matches what's listed on the app's official store page before installing an update.
- After install, Android may prompt you to allow "Install from unknown sources" — approve only this one install, then revoke the permission in Settings > Apps > Special access.
- We link directly to the APK file or the publisher's repository; we do not modify the binary. Always run a virus scan after any sideloaded install.
About this app
You can use it to exchange private encrypted and covert chat- or email messages or store your own encrypted notes on your phone.
See our demo videos:
* Introduction
* Encrypting Emails
* Encrypting Images
Oversec is completely agnostic of the subjacent app, it works with Whatsapp™, Line™, Snapchat™, Instagram™ or any other chat app. It also supports sending and receiving PGP encrypted messages with the Gmail™ or any other Email app.
End-to-End Encryption was yesterday. Oversec introduces "Eye-to-Eye" encryption. Encrypted data is only decrypted while it is shown on the screen! No clear text is ever persisted and thus cannot be extracted from the file system or accidentally be backed up into the cloud.
We also carefully designed Oversec so that it doesn't require internet access. Because of that, you can rest assured that no decrypted information can ever leave your device.
How it works:
Oversec constantly monitors the text on your screen. When it finds an encrypted text, it tries to decrypt it and then shows the decrypted text as an overlay in place of the encrypted text. Conversely, it can read text out of an input field, encrypt it, and then put the encrypted text back into the input field.
In order to encrypt a text, Oversec shows a button next to an active input field. After having entered the secret text, tapping that button makes Oversec read the text, encrypt it and put back the encrypted text into the field. It is now ready to be sent in the subjacent app as usual - the app doesn't even know that it is sending encrypted data!
Oversec also features a unique way of encoding the encrypted messages. It stores the encrypted text in invisible (zero-width) characters and let's you add decoy text at the end. That way, a message will just show e.g. "The sun is shining!" with no visible sign of any encryption, whereas in reality it contains a hidden encrypted message.
You may also encrypt and send photos through Oversec - its unique camera mode even allows you to take and send an encrypted photo without ever storing the original photo on the device.
Oversec encrypts your data either using symmetric keys (using ChaCha20 cipher + Poly1305 MAC ) or using asymmetric PGP encryption (making use of the OpenKeychain app).
The code is open source and can be found here.
This app uses Accessibility services.
Details
| Version | v1.5 |
|---|---|
| Size | 5.26 MB |
| Developer | oversec |
| Category | Text Encryption |
| Package | io.oversec.one |
| Android | 4.1+ |
| Last Updated | Oct 31, 2026 |
| Downloads | 10 |
Frequently Asked Questions
Is Oversec free to download?
Yes. The APK file linked from this page is free. The developer may offer in-app purchases once installed, but obtaining the installer itself costs nothing.
What Android version does Oversec require?
Android 4.1+ or newer. Installing on older devices may cause crashes or refuse to install.
Is Oversec safe to install?
We link to the exact APK published by oversec. We do not modify the file. Still, as with any sideloaded app, scan it with a reputable antivirus before opening it, and only grant permissions the app genuinely needs.
How do I update Oversec?
Install the newer version on top of the old one — Android will keep your data. If the signature differs, uninstall first (you may lose local progress).
Why is the app not installing?
Common causes: not enough storage, an older Android version than 4.1+, or a conflicting build already installed. Free up space, check your OS version, and uninstall any previous copy before retrying.
How to Download & Install Oversec
- Tap the Download APK button above and save the file to your device.
- Open your device Settings → Security (or Apps → Special access → Install unknown apps) and allow your file manager or browser to install unknown apps for this one file only.
- Open the downloaded
io.oversec.one.apkfile from your Downloads folder. - Tap Install and wait for Android to finish.
- Open «Oversec» by oversec and grant only the permissions it actually needs.
- Revoke the "unknown sources" permission once you are done installing.
Note: this page hosts or links to the installer only. The application name, icon and description are provided for identification. All trademarks belong to their respective owners.
