Kryptos
Rude and unsafe words are out of the text steganography dictionaries, still 4096 words per language. Covers made by the word and sentence modes cannot be read by versions before 2.3.2, both sides have to update.
Keyboard: bigger buttons, adjustable field size, the badge can be hidden.
Send after encrypting now works in messengers with their own send button.
Profiles and contacts can be renamed.
Around twenty fixes.
The Kryptos keyboard installs like any other system keyboard: turn it on once and it is there everywhere you type. Write your message in WhatsApp, Telegram or an SMS, tap the padlock, and what is left in the field is the ciphertext, ready to send. Incoming messages Kryptos decrypts by itself, right over the chat as you scroll it, with nothing to copy and nowhere to switch. Both the keyboard and the on-screen decryption are built into the system, so they work in any app.
It is the same app on iPhone and on Android and the two are fully compatible. It does not matter which phone your contact has.
The encryption is the real thing: the Signal Protocol through Signal's own libsignal library, a fresh key for every message and protection even against future quantum computers. A contact can be verified by safety number. When a full chat is more than you need, there is a simple mode built on one shared password, and for those who live on PGP that is built in too. All the messenger ever sees is a meaningless run of characters, with no recognizable markers.
Steganography hides the very fact that you are writing: the ciphertext can be buried inside an ordinary photo or disguised as a harmless run of real words. Without the password there is nothing in the photo to test for.
Nothing goes online: there is no networking code in the app at all, and the build ships without the INTERNET permission. It asks only for the camera to scan QR codes, vibration and overlay control. No accounts, no phone number, no servers, no analytics. Keys are created on the phone itself, kept in the Android Keystore and never leave it.
Entry can be closed off with biometrics or a passcode. There is also a panic password: typed into the same field, it wipes everything for good instead of unlocking. The clipboard clears itself, messages can disappear on a timer, screenshots and the app-switcher snapshot can be blocked, and all your keys can be exported into one password protected file to move them to a new phone.
Also inside: light and dark themes, an app language separate from the system one, a step-by-step guide with answers to common questions, and a keyboard with suggestions, autocorrection and emoji for English, Russian and German, entirely offline.
- Author: datakeeper
- License: GNU Affero General Public License v3.0 only
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Versions
Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.
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arm64-v8aarmeabi-v7aThis version requires Android 8.0 or newer.
It is built and signed by the original developer, and guaranteed to correspond to this source tarball.
Download APK 22 MiB PGP Signature | Build Log
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arm64-v8aarmeabi-v7aThis version requires Android 8.0 or newer.
It is built and signed by the original developer, and guaranteed to correspond to this source tarball.
Download APK 21 MiB PGP Signature | Build Log
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arm64-v8aarmeabi-v7aThis version requires Android 8.0 or newer.
It is built and signed by the original developer, and guaranteed to correspond to this source tarball.
Download APK 20 MiB PGP Signature | Build Log
- Full German: interface, QWERTZ layout with its own dictionaries, steganography.
- Length masking now covers steganography too.
- Android: the lock key can send the message right away.
Fixed
- On-screen stego decryption broke on names and stray words.
- The key preview showed in screen recordings inside password fields.
- Stalls on launch, on long clipboard text and in PGP are gone.
The stego format changed: older builds will not open length-masked messages.
* Panic password: a second password that wipes everything instead of unlocking.
* App passcode, for unlocking without biometrics.
* Key backup: your keys, contact keys and PGP keys in one password protected file.
* Argon2id everywhere, PBKDF2 removed.
* Photo steganography rebuilt: no visible signature, keyed adaptive placement.
* On-screen decryption finds messages in real messengers again.
* Password protected messages and stego photos from older versions no longer open.