Common terms used in computer security: -Virus: A program that replicates itself across a network, or the Internet as a whole. The virus payload may be destructive, like deleting files, or it could simply try to overwhelm a network by copying itself. -Worm: A virus that replicates itself without human intervention. If the victim has to open an e-mail attachment to get infected, it's a virus. But if it scans for new victims and attacks by itself, it's a worm. -Trojan horse: A program that doesn't necessarily replicate itself, but like the legendary wooden horse is much more than it appears. A Trojan horse program might look like a game, but instead it steals your personal information and sends it to a criminal. -Password sniffer: A file that seeks out passwords on your computer, then sends them to a hacker. A keylogger can also grab anything typed on the keyboard. -Blended threat: A program that combines the characteristics of viruses, worms and Trojan horses. A blended threat, like the recent Nimda outbreak, is a recent phenomenon. -Exploit: A program that takes advantage of a security hole in a computer program, like Microsoft Windows or AOL Instant Messenger. -Spyware: A general term for a program that surreptitiously monitors your actions. While they are sometimes sinister, like a remote control program used by a hacker, software companies have been known to use spyware to gather data about customers. The practice is generally frowned upon. These are all good as long as they have Federal Bureau of Investigation approval like the magic lantern.