Have a secret that you want to share? Why not hide it in a picture?
About this app
Have a secret that you want to share? Why not hide it in a picture? With PixelKnot, only your friends with the secret password can unlock your special message. Everyone else just sees a pretty picture. It’s a fun and easy way to share hidden messages without anyone knowing. Take those pixels, twist them in a knot, and see for yourself!
★ DISGUISE YOUR MESSAGES: Pictures are public, the text is hidden inside. Even a trained eye will think the image is unedited. It’s security through obscurity! ★ FOR YOUR EYES ONLY: Put a password on the secret message to make sure that no one can read it except the person it’s meant for. ★ EASY IMAGE CHOOSER: You can use the camera to take photos, or just use photos you’ve already taken. ★ INVISIBLE CHANGES: Even a trained analyst analyst shouldn’t be able to detect any message. The image bytes should seem undistorted. ★ SHARE ACROSS PLATFORMS: Want to share the images over email, file sharing tools (like Dropbox & Sparkleshare), social media (like Google+ & Flickr) or directly through Bluetooth or NFC? Not a problem! The messages are still recoverable on the other side. We'll have even more tools (like Facebook) working soon, so stay tuned! ★ AD-FREE: We want your love, not your money. ★ MATHEMATICALLY SECURE: We use the F5 steganography algorithm which implements matrix encoding to improve the efficiency of embedding and employs permutative straddling to uniformly spread out the changes over the whole steganogram. ★ ATTACK RESISTANT: We’ve launched attacks on images with messages hidden in them using a specialized version of stegdetect, an automated tool for detecting steganographic content in images. In most cases, the pictures have been impervious to attack. We will be including detection in an upcoming version of the application so you can easily test it yourself! Don’t see your language? Join us and help translate the app: https://hosted.weblate.org/projects/guardianproject/pixelknot https://hosted.weblate.org/projects/guardianproject/pixelknot-metadata
***Learn More*** ★ ABOUT US: Guardian Project is a group of developers that make secure mobile apps and open-source code for a better tomorrow. ★ OUR WEBSITE: https://GuardianProject.info. ★ ON TWITTER: https://twitter.com/guardianproject ★ OPEN-SOURCE: PixelKnot is free software. You can take a look at our source code, or join the community to help make it even better: https://github.com/guardianproject/pixelknot ★ MESSAGE US: Are we missing your favorite feature? Found an annoying bug? Please tell us! We’d love to hear from you. Send us an email: support@guardianproject.info
***Disclaimer*** The Guardian Project makes apps that are designed to protect your security and anonymity. The protocols that we use are widely regarded as the state of the art in security technology. While we are constantly upgrading our software to combat the latest threats and eliminate bugs, no technology is 100% foolproof. For maximum security and anonymity users must utilize best practices to keep themselves safe.
Licensed under GPL-3.0-only, by Guardian Project.
What's New in v1.0.2.1
Imported from the F-Droid repository index.
Version history
Jun 9, 2022 · 2.9 MB · Android API 21–30 · code 1021
Imported from the F-Droid repository index.
SHA-256 17e656afff7fd6864f41a9bf2d661a9fd1545731def623fd7f45411b6a1cd3d3
Feb 18, 2017 · 1.9 MB · Android API 17–25 · code 101
Imported from the F-Droid repository index.
- Big update to v1.0.1:
- * Fix in JPEG encoding to defend against detection attack
- Big update to v1.0.0:
- * A brand new user experience... simple and streamlined!
- * Now compatible with the latest Android OS and devices
- New and improved in v0.3.3:
SHA-256 ca0d4f40e95078a5d5f709f7d7e21357a0412fdc4fd42ab68373cba9a98850f5
Nov 22, 2016 · 1.9 MB · Android API 17–25 · code 10
Imported from the F-Droid repository index.
SHA-256 79c1ba7d8e602e9d76491ae0510230103bbec5a0c5fbd2f7fe8dfff1e1054cf1
Will it run on your device?
87%
- Runs on a broad range of modern Android versions.
- Multiple CPU architectures are covered.
Installation Guide
Open Settings on your Android device
Go to Security → Unknown sources (or Install unknown apps)
Enable "Allow from this source" for your browser or file manager
Open the downloaded APK file from your Downloads folder
Tap "Install" and wait for installation to complete
Launch the app from your home screen
Make sure to re-enable Unknown Sources restrictions after installation for security.
How to install this safely
How to verify the file you downloaded
Before you install anything, confirm the file is the one described here. On a computer, run shasum -a 256 your-download.apk (macOS or Linux) or certutil -hashfile your-download.apk SHA256 (Windows), then compare the output character-for-character with the SHA-256 on this page. If a single character differs, the file is not the build we recorded — delete it.
What the signing certificate proves
Every Android app is signed with a private key that only its developer holds. The fingerprint on this page is a hash of the matching public certificate, and it proves continuity rather than identity: it tells you a build came from whoever signed the earlier ones. Android enforces this at install time — if a package claiming to be info.guardianproject.pixelknot is signed with a different key, the system will refuse to install it over your existing copy. A fingerprint that changes between releases is worth pausing on, because a repackaged app that has been modified by someone else cannot keep the original signature.
How to roll back to an earlier version
If the current release misbehaves, 1.0.1 is the last build before it. Android will not install an older version code over a newer one, so you must uninstall PixelKnot: Hidden Messages first — which clears its local data unless you have a backup. Reinstall the older APK only if its signing fingerprint matches the build you already trust, and check the API range: an older release may target an Android version your device has moved past.
Why we list sources instead of hosting everything
The official store channel is almost always the right choice: it updates automatically and carries the publisher's own distribution guarantees. A direct APK is useful when a device has no store access, when a rollout has not reached your region, or when you need a specific version — and only when the publisher has authorized that copy. APKBrowse does not list pirated, cracked, or unauthorized rebuilds of PixelKnot: Hidden Messages, and a listing is removed when the evidence for it stops holding up.
Get PixelKnot: Hidden Messages
Every source we list for info.guardianproject.pixelknot is legality-reviewed. Pirated or cracked builds are never offered.
Other sources
F-Droid listing
officialF-Droid builds this app from source and signs it. This is its official listing, with older builds and full release notes.
Source code
verified publisherThe upstream repository this build is compiled from.
We check legality and signature continuity, but device behaviour still varies. Install at your own discretion.
App Information
Security Verification
We record provenance; we do not run malware scans. Verify the hash yourself before installing.
SHA-256 Hash
17e656afff7fd6864f41a9bf2d661a9fd1545731def623fd7f45411b6a1cd3d3
Signing certificate
af0d13a1d236a1f8d232e916cbc01fafe2305e54d9eb66961df80374c01e146e
Permissions Required
What each permission lets PixelKnot: Hidden Messages do. A highlighted one is worth a second look — not necessarily wrong, just worth asking whether this app needs it.
Previous Versions
The signing certificate fingerprint for this release is on record, so a build that does not match it did not come from this publisher.
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