I am running Ubuntu 12.10 on my laptop and I would like to make a set up such that without a login password, no one would be able to login into my system. Currently it seems that one can, quite easily, login into Ubuntu operating system using the recovery mode, or using an Ubuntu Live USB. When I realized that the system can be logged in so easily without a password, I wonder what's the purpose of the login password anyways !
Anyhow, how can I temporarily disable recovery mode and live USB boot? If there are other ways to get into USB, I would like to know that as well.
This is to prevent my roommate from getting access to my laptop when I go for vacation. So if some logging method requires a change of password before displaying my home directory, that's a less significant security risk for me, 'cause then I wont be able to login myself and will "detect" that someone has used my system (so your friend wont do that 'cause he knows you will find out and more importantly cannot login anymore).
Also I would like to password protect USB ports temporarily so that data cannot be copied out (or a keyloger cannot be copied in) without entering my root password.