I'm creating a hacking challenge as a project in university.
Somewhere in the middle of the challenge the challengers will receive a user name "guest" and a password to enter one of my Linux virtual machines (via ssh).
I want this "guest" to be able to read only one specific file (just read and not to modify or delete), and I also want to make sure this user can't write, read, create, delete or modify any other directories and files (except that one specific file I had mentioned before).
How do I create such a user and such a file?
