Really basic app that has strong encryption and authentication through passport.js and OAuth.
This was done as security and authentication practice on the course "The Complete 2020 Web Development Bootcamp". All the javascript is written by me.
The end result is a bit different on the backend than the course example. The user submitted secrets are not saved on the user itself, but added to their own collection which in the case of data breach will still keep the user submitted secrets anonymous.