Popular Science: “Whether you’re in an open office where colleagues regularly wander past, or live somewhere—like a college dorm—where you feel comfortable leaving your laptop unattended in the presence of relative strangers, it can be all too easy for someone else to sneak a look at your computer. If you want to keep your device secure in communal environments, your best bet is to stop unauthorized access in the first place. Still, there’s some detective work you can do if you suspect someone else has been using your device…”