Welcome to Cryptully’s documentation!


Cryptully is an encrypted chat program meant for secure conversations between two people with no knowledge of cryptography needed.



  • Provides basic, encrypted chat with no prerequisite knowledge of cryptography
  • Runs on Linux, Windows, and Mac OS X
  • No registration or software installation required
  • Chat with multiple people simultaneously
  • Ability to host your own server (for the technically inclined)
  • Graphical UI and command line (Curses) UI
  • Open source (LGPL license)

How does it work and how is it secure?

Cryptully works by relaying messages from one person to another through a relay server. It generates per-session encryption keys (256bit AES) that all communications are encrypted with before leaving your computer and then decrypted on the destination computer.

Quick Start

  1. Download the executable for your platform on the Downloads page.
  2. Launch the executable (no need to install anything).
  3. Select a nickname and connect to the server.
  4. Enter the nickname of the person you want to chat with.
  5. You should now be chatting!

Need more info? See the Using Cryptully page for much more detailed instructions.

Doesn’t encrypted chat already exist?

Yup, it does. There are plenty of other encrypted chat programs so what’s the point of Cryptully? The problem is just that, there’s plenty of other chat programs. There’s too many options for chating with another person. Other solutions require downloading and installing software, creating accounts, etc. With Cryptully, you just download and run the software. No need to install anything or create an account. Just enter the nickname of the person you want to chat with and you’re off.

Another advantage is that Cryptully is a relatively simple program and is open source. For the paranoid, you can inspect the source code to ensure that Cryptully is not doing anything nefarious or host your own relay server.


For non-programmers:

Even if you’re not writing code, you can still help! Submitting any issues or problems you run into at https://github.com/shanet/Cryptully/issues or by emailing shane@shanetully.com. Even reporting something like a section in the documentation not being as clear as it could be or just a typo is helpful.

For programmers:

If you would like contribute to Cryptully, see the Downloads page on how to set up a build environment and get the source code. Please any issues encountered at https://github.com/shanet/Cryptully/issues.