μCrypt Messenger: A secure & simple end-to-end encrypted chat

µCrypt (or muCrypt) is a simple end-to-end encrypted chat. The server is written in Python and the client in JavaScript.

A goal when creating µCrypt was to enable the chat to be audited very easily, because of that the lines of code (minus HTML/CSS) was limited to <200 lines of code in total.

In an attempt to be fully transparent with the user, the client displays a "raw message" bar at the top, enabling the user to monitor exactly what data is being sent to/from the chat.

µCrypt is intended to act as a decentralised chat platform, with users setting up their own servers for their own use, however, a demo is provided here (Please don't abuse).

• Python 3
• Python websockets
• Python ssl
• Python asyncio

• Any modern web browser

This step isn't essential. If you've never used venv before, don't bother with this step.

• python3 -m venv mucrypt
• cd mucrypt
• source ./bin/activate

• pip3 install websockets asyncio ssl

• wget https://raw.githubusercontent.com/connor-brooks/muCrypt/master/server/server.py

Using a text editor to modify the following lines of server.py to reflect your servers certificate paths:

• cert = "/path/to/ssl/cert.pem"
• privKey = "/path/to/privkey.pem

Enter the directory you wish to serve the HTML client from, in this example, the path /var/www/html/mucrypt is used.

• cd /var/www/muCrypt
• git clone https://github.com/connor-brooks/muCrypt
• mv muCrypt/server/* .
• rm -rfv muCrypt

Using a text editor modigy the following lines of script.js, changing example.com to your own domain:

• var ws = new WebSocket("wss://your-domain.com:8765/");

To run the server, simply run:

• Run nohup /path/to/your_server_script/server.py &
• if you are using the venv, remember to run source /path/to/your/venv/bin/activate first.
• Setting up an init script would be an easy way to keep the server running automatically. For information on how to do this with a venv, see here

• Currently, if your connection drops due to connectivity issues or a locked phone screen, you won't be able to send or recieve messages until the page is reloaded