A friend of mine sent me this, and I figured you guys would appreciate it. A stick figure walks through the history of AES, and how it works. I didn't get much after Act II, but it's still a fun read.

http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html

This is cute, and pretty good.

Very clear and simple, thanks for sharing! I like the included Foot-Shooting Agreement, as well. I must say that as many times as I have dealt with LFSR-based crypto, this helped firm up a few things.

Fun read -- never really looked into AES before, but after reading this I get the gist of it. Thanks for sharing!

I have to disagree with their idea of "foot-shooting prevention". Yes, it's true that most people have no need to implement AES - that's not because they need to worry about side-channel attacks, but because there are multiple free software implementations already out there that are much better than whatever hacked-together implementation I might write in an afternoon.

But if you're writing cryptographic software, there are so many other ways you can shoot yourself in the foot that have nothing to do with the underlying ciphers you're using. (See: the use of CBC in SSL.) Side-channel attacks are just one of many considerations, and generally not the most important.

So really I would go a step further: you shouldn't try to implement AES, or any other cipher, without knowing what you're doing, but furthermore, you shouldn't be designing any kind of cryptographic protocol without knowing what you're doing. Telling people that using off-the-shelf crypto libraries will stop them from shooting themselves in the foot may actually make the problem worse.