|
Arnezami:
Thanks for clearing things up... It seems i missed the fact that the optical drive also has a part in this play (Maybe you could add this to your drawing as well? :P)
I have another question or two though... (sorry for not reading all the details on how AACS works).
1. From my understanding, Hpriv is never relly needed for anything else but calculating Hsig. Why on earth would the Hsig be calculated in software, and not on the actual optical drive? Calculating it in the player would expose it to attacks like this, but from what I can see, the other components of Hsig is far less sensitive than Hpriv, and could be sent to the drive for Hsig calculation.
2. You have a complete sniff of the comunication with the drive during this sequence, correct? If these design specs are 100% correct, you should have a sniff of the Hpriv, so if you can't find it, it is probably because your analysis software has flaws.
All in all i do get a feeling that there is something missing from this picture though. The Hsig calculation seems like a red herring to me as I can't see any reason why the Hpriv should need to be accessible outside of the optical drive. Could it be that there are "secret specifications" that says "disregard figure x.x on page x. This is just written to throw off the hackers..." Or... "Hpriv should be encrypted before Hsig is calculated"...
Again, I don't have a good understanding of this system, so it may just be that I'm missing something...
|