Discrypt от Khafra

Discrypt is an add-on for Discord for those who want more privacy.

Messages sent on Discord are sent in plaintext to the server, allowing them to be retrieved, read, or examined at any time. Discrypt encrypts the content before it reaches the server and only allows those with the set password for that message to decrypt.

The extension is open-sourced at:
https://github.com/khafradev/discrypt (MIT License)