Discord message encryption plugin, it gives end-to-end clientside encryption for your messages and files with automatic key exchange
When you opened discord you will get a window to create your database (stored locally), once it's done & ready, you can simply enable the encryption by toggling the lock icon visible to the channel's top and you can chose the key used besides that. You can go in the menu by right clicking the lock icon. DM channels have other options than group channels for global encrypted communication.
It is totally open-source!
More information on: https://github.com/HyCore/ShulkerRoadCrypt/