How to protect data on USB

i added local external storage, now i can add stuff to the usb storage through the webinterface/app.
but now when i take the usb out of the Raspberry pi and stick it on my pc/laptop i can see the files in it.

is it possible to protect/secure them so it doesn’t show?

thank you

Hey, I believe you can use LUKS for this type of thing. Maybe this will be of use:

Maybe encrypt it via Nextcloud?

In theory (you need database at the same time for recovery, sharing and other apps can make problems and the whole code is more complicated and less tested). In this case I think OS-based disk encryption is more stable, better tested and more reliable.