CPS2 Algo done.
 
Nicola Salmoria of MAME Dev seems to have worked out the rest of the CPS2 algo (though there is still some s-boxes to complete), to quote his blog...

• Take the 16-bit address and a 96-bit key and run them through the first Feistel network, to produce a 16-bit subkey.
   
• Take the 16-bit ciphertext, 16-bit subkey, and another 96-bit key and run them through the second Feistel network, to produce the 16-bit plaintext

Our congratulations go out to him, again to Andreas Naive and also Charles MacDonald who all played a role to get to this point today.
 
Looking back at the way things have gone from the first XOR release some six years ago (after the discovery of the main weakness in the system), we know some people were quite unhappy at our unwillingness to have this algo known for emulation (Statement of 7th Janurary 2001). It was always our intention to hold back information to help achieve this until the system was commercially dead (our view was 3 years after the last game released). It is very satisfying to know we achieved this as believe it or not Janurary 2007 is just past that three year mark (Hyper Street Fighter II was released in December 22nd 2003).
 
I will update the encryption page with the details once Nicola has fully documented the Algo within MAME.

CPS2 Algo mostly done.
 
It looks like Andreas Naive has mostly worked out the CPS2 algo. Congratulations go out to him for working it out, now seems like a good time for it to go as the system is dead. From his Blog (I don't read Spanish) it would appear that he only used 16 tables from Jyangokushi to do it. I must say that I am very happy he did not discover the 10 tables from SFZ we released back in 2003 as that would have been to early for it to go in my Book.