Can my JSON editor web app design be simplified? [closed]

My aim is to build an app for personal use which provides an editor that saves / loads an encrypted JSON file from the server. The editor should have syntax highlighting and the decryption key should remain on the client since the webserver might be controlled by a third party. The app should be accessible from any device that has a web browser

After doing research, I have found the following -

• Server side framework - express.js / node
• Authorisation - express-session / connect-redis
• Embedded JSON editor - ace.c9.io
• Front end symmetric encryption - aes-js

My main concern is that the above solution is overly complex for these requirements. Could it be simplified?