So, I saw this information on an irc chat one day, that apparently the leaked SDK's makerom has information on how to decrypt roms, or at least obtain the keys, and I decided to further it with some of my own rom dumps for testing purposes, as well. What this application does, is generates keys for the different rom partitions (romfs, exefs, and exheader). It's 100% legitimate.
Simply open your 3DS or 3DZ (I need confirmation on this format, as I cannot dump them at this time) rom, and choose a key type, then press "Get Key!". It'll appear in the box below, and you can also choose to save the keys to a text file after you've generated them. It's stupidly simple.
As of now, the keys do not have any practical use, but it's a step closer to rom hacking on the 3DS.
What are you waiting for? Download it here:
http://bit.ly/3DSKeyGen(The bit.ly is for statistical purposes. It's only flagged because it has the words "key generator" in the original name. Rest assured, it's safe, you can even build the source below as proof in VS C# 2010.)
And for all the irredeemable fuckwits that think this is fake, here's the source:
https://dl.dropboxusercontent.com/u/34957059/3DS Rom Decryptor Key Generator source.zip