Now Playing: 11-28-12 Marketplace Tech Report

The hotel room lock that uses not a key but a card may present a big problem: A simple hack that can make for an easy burglary. It requires a $50 piece of hardware called a microcontroller. A software engineer showed off how to do it at what's called the "Black Hat" hacking conference last summer. What is a black hat hacker? It's the more mischevious version of a white hat hacker.