If you are still trying to figure out what DES was all about then it's time to give up and try out AES in whole new and easy-to-understand way - try a stick figure guide.
You may think that a tutorial video, or perhaps a podcast, is a good way to catch up on complex technical ideas, but what about a cartoon? Xkcd has perhaps proved that you can tackle difficult topics in cartoon format - but AES?
A few years ago the National Institute of Standards and Technology decided that the original Data Encryption Standard (DES) needed a replacement and asked for suggestions. In the end the "winning" suggestion was based on the Rijdeal Cipher and this is now what we refer to as the Advanced Encryption Standard (AES). It is what most government departments use and is approved by they NSA - which is both a blessing and a curse given its standing at the moment.
If you examine the description of the AES then you have to conclude that it is complicated. In fact, before you attempt to encrypt anything with AES, you first have to decrypt its specification. This is where Jeff Moser's brilliant cartoon strip comes into play.
It is a funny, readable and eventually understandable description of AES:
"A Stick Figure Guide to the Advanced Encryption Standard (AES)
(A play in 4 acts. Please feel free to exit along with the stage character that best represents you. Take intermissions as you see fit. Click on the stage if you have a hard time seeing it. If you get bored, you can jump to the code. Most importantly, enjoy the show!)"
As you might guess from the "4 acts" part of the description this isn't a four-frame cartoon - it goes on for quite a few pages and it is also available as a slideshow.
Warning! This is very much not suitable for math phobes. You will encounter traces of math in this cartoon.
That said Act 1 is a summary of the history of how we got to AES from DES and doesn't have any math in it. Act 2 covers some basic cryptography. Act 3 is where the AES is described in some detail - well for a stick figure cartoon it really is amazing detail! And finally Act 4 is a summary of the math that you need to know to make sense of it all.
Not only a great introduction to AES, the cartoon it provides an example of how you could use the same approach to explain other complicated ideas. I have a feeling that it might go horribly wrong if not implemented with sufficient humour and wit - but anyone for "Stick Figure Does Rocket Science"?