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PixelKnot: Hidden Messages

Have a secret that you want to share? Why not hide it in a picture?
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.

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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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  • Version 1.0.2.1 (1021) suggested Added on Jun 09, 2022

    arm64-v8a armeabi-v7a x86 x86_64

    This version requires Android 5.0 or newer.

    It is built by F-Droid and guaranteed to correspond to this source tarball.

    Permissions
    • read the contents of your shared storage
      Allows the app to read the contents of your shared storage.
    • control vibration
      Allows the app to control the vibrator.
      (4.3)
    • modify or delete the contents of your shared storage
      Allows the app to write the contents of your shared storage.
      (4.3)

    Download APK 2.9 MiB PGP Signature | Build Log

  • Version 1.0.1 (101) - Added on Feb 18, 2017

    arm64-v8a armeabi armeabi-v7a mips mips64 x86 x86_64

    This version requires Android 4.2 or newer.

    It is built by F-Droid and guaranteed to correspond to this source tarball.

    Permissions
    • read the contents of your shared storage
      Allows the app to read the contents of your shared storage.
    • control vibration
      Allows the app to control the vibrator.
      (4.3)
    • modify or delete the contents of your shared storage
      Allows the app to write the contents of your shared storage.
      (4.3)

    Download APK 1.9 MiB PGP Signature | Build Log

  • Version 1.0 (10) - Added on Nov 22, 2016

    arm64-v8a armeabi armeabi-v7a mips mips64 x86 x86_64

    This version requires Android 4.2 or newer.

    It is built by F-Droid and guaranteed to correspond to this source tarball.

    Permissions
    • read the contents of your shared storage
      Allows the app to read the contents of your shared storage.
    • control vibration
      Allows the app to control the vibrator.
      (4.3)
    • modify or delete the contents of your shared storage
      Allows the app to write the contents of your shared storage.
      (4.3)

    Download APK 1.9 MiB PGP Signature | Build Log