Chown and chmod. Why?

Why do we need to use chown to chang the owner and group for our keyfile?
Why do we need to chmod 600 our keyfile?

Theoretically, evrything should work with EVEN MORE permissions given to this file. I shouldn’t need to 600 my keyfile for mongod to run properly (mongod wont run if you don’t 600 your chmod keyfil).

For better security
These are for authentication and we don’t want others to read/edit these files
In Unix strict/restricted permissions needed for keyfiles,opn ssh key files etc

600 permission means: I (owner) can write and read the file, everyone else can’t.