I have a LAMP system running (of an SD card on small computer) that monitors some arbitrary data. I return the data as JSON from the page so that it can be used in whatever reason its fit for.
I would like to protect the PHP SOurce files and other code from prying eyes. I know that the root and user password MUST be very strong to prevent brute or lucky entry.
How would I prevent users from accessing any data within the Linux OS (/usr; /etc) when they take the SD card out and try and mount it or extract it on another system?
-EDIT
I found this for FreeBSD how can I configure it for Ubuntu?
The best way and most difficult for any intruder is to use LVM and a separate USB key to store the key data for auto decryption.
This answer is very close to what I have asked
https://askubuntu.com/a/90911/37108
But there are other ways to achieve what I need without a separate USB key but pointed out that it is very easy to hijack grub and boot into root with full access.