glossary

Here follows a list of as much of the jargonny stuff that you might not understand (who says I do too?).

Hash
An encoded password, file or any other data. Hashing is done for a number of reasons most commonly encryption and error-checking. It is a long and (well, almost) unique string of characters that is created by passing the text/password/file through one or more mathematical algorithms. These algorithms are usually a one-way process, meaning you cannot retrieve the original file/password from reversing the hashing process itself.
The resulting hash can then be compared to the hash from another file to check if they are the same - whether it is a password (stored securely), or a file you have downloaded and want to be sure it hasn't been corrupted or infected with malware.

Malware
Any computer program or code that you wouldn't want on your computer. Usually placed there by someone naughty, or accidentally installed.

Pen Testing

Also known as Penetration Testing. This is the perfectly legal job of attempting to gain access to a website/network/database in order to find the security flaws. The law is very strict on this kind of thing, so pen testers (or 'White Hats') must always obtain written permission from the owner of the system being tested, and potentially the approval of hosting providers, ISPs, and other bodies too.
It is a highly skilled and inventive job, which also involves quite a bit of paperwork...