Router Privacy

Here's the situation: my roommate controls the modem and the wireless router for the house. The problem: I don't really trust him. I know that he tries to invade the privacy of everyone that lives in this house. I've even caught him trying to get on my computer while I was out of the room on multiple occasions. He knows a lot about Windows and Unix operating systems and he really knows his way around a Mac.

My question is: How can I ensure that he can't see what I look at on the internet and files/programs on my computer?

Thanks in advance.

First thing to do is get a new roommate!

Depending on the router he may be able to log your network activities. It's not so easy to get around that but the first thing to do is select a strong password for your Mac user accounts and turn of sharing of any kind in system preferences.

You could look at using a secure proxy/VPN with would encrypt your internet traffic.

Depends how far you want to go to defeat this unfortunate individual.