USB key to pass password in Centos 6

Andrew asked:

I had a room mate that put a livecd in my desktop and looked around on my machine. I caught him in the act and threw him out.

I haven’t had a room mate for a while now and so as to avoid the livecd issue again I encrypted the hard drive, the machine is running centos 6.3.

Is there anyway that I can avoid typing the password in each time if I have usb key in the machine to feed the password to the system?

Additional question.

Is there anything you can suggest to solve the problem I have ? Thanks