degod

 degod 0.5 decrypts ADX files. It has support for God Hand, Okami, Killer7, 
Samurai Champloo, Blood+, Raiden III, Phantasy Star Universe (and the
expansion),
Senko no Ronde, NiGHTS: Journey of Dreams, and possibly others.
In case you come across a game that uses a different encryption key, degod has 
brute force key guessing functionality built in, but I recommend using guessadx
0.2
now, as it has a much better algorithm. 0.2 fixes an off-by-one array overwrite
from 0.1.
Also, since r534 vgmstream has been able to decrypt files on the fly, 
using the set of keys built into degod, so you probably shouldn't bother with
manually
decrypting anymore.