PixelKnot: Hidden Messages is an app by The Guardian Project in the Communication category, listed since at least June 2023. It includes native code for x86 32-bit, x86 64-bit, ARM 32-bit and ARM 64-bit, so it runs on practically every phone.
It asks for 1 permission, 1 of them sensitive: read shared storage.
What's new in v1.0.2.1
- many translations added
- updated to Android 11 / SDK 30
- add support for Signal and Telegram as preferred sending channels
- update AES encryption code
- improve performance, stability
- make app movable to SD card
Description
From the listing uploaded by “appupdater”.
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 newly developed steganography algorithm F5 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: [email protected]
***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. PixelKnot is still an experimental application and should not be used in real world deployments. You can find a good introductory guide to these topics at https://securityinabox.org
Security & authenticity
Security rating: Trusted
Signing certificate
Signature matches the Google Play versionChecked by the source store on Nov 21, 2025.
Certificate issued to “guardianproject.info”This is the certificate of the Google Play version.
Store checks and file details
Developer signature not checked yetMay 11, 2026
Validated against Google PlayNov 21, 2025
Signed byCN=Guardian Project, OU=guardianproject.info, O=guardianproject.info, L=New York, ST=New York, C=US
Uploaded by “appupdater”Gold tier · 117,810 followers · uploading since 2020
Scans and ratings come from the source store; the certificate comparisons are AAPKs's own, made from the files' published signatures. AAPKs doesn't scan files itself — compare the MD5 and signer after downloading.
Permissions (1)
PixelKnot: Hidden Messages requests 1 permission, 1 of them sensitive.
PixelKnot: Hidden Messages APK: questions and answers
Can I install this APK over the version I already have?
Yes, if your installed copy is older. It is signed like the Google Play version, so Android installs it as an update and keeps your data.
Is the PixelKnot: Hidden Messages APK safe?
No one can promise that a file is safe, but some things can be checked. The source store rates this file Trusted. Its signature matches the Google Play version. After downloading, check that the file's MD5 is b468787be459c85accce0e7b73c7adce.