~ Cryptography ~
I found an article that is the most concise and simple explanation of cryptography that I have ever read. Here is the link to the article.
Additionally there is a carry on to this article that describes quantum key distribution. Here is a link to that article.
Finally here is a page on the difference between quantum cryptography and classical cryptography. Here is the link to that article.
These articles are on the same wiki site which contains this wonderful comment about a situation that troubles me constantly.