(More) Specifics:

• Undoing the protection should include filling in a password.
• The password should be different from the one used with sudo or any other passwords that are used for acquiring elevated privileges.

All (possible) solutions and suggestions are welcome! Thanks in advance!

Edit: Perhaps additional specifications:

• With 'displace‘, I mean anything involving that resembles the result of mv, cp (move, cut, copy) or whatsoever. The files should remain in their previously assigned locations/places and should not be able to ‘pop up’ anywhere.
• I require for the files to be unreadable.
• I don’t care if it’s modifiable or not.
• I don’t require this for my whole system! Only for a specific set of files.