Google Keep is like this, but their editor is very basic, and everything is saved in plain text in Google's server.

So I created notenote.cc, an Instagram style note taking app, and everything is encrypted on your device before sending to server.

Take unlimited text notes for free, and pay only $1.99 / month to attach photos and short videos.

Source code to check how your notes are encrypted and saved: https://github.com/penghuili/notenotecc