It was just figuring out what computer specific bits iTunes used to encrypt the keyring that was the real trick here. Given the fact that iTunes can play the song without being connected to the network, once iTunes is authorized, everything required had to be on the machine somewhere. That was the whole of the protection involved, really.
ITUNES DRM CONVERTER CRACK HOW TO
The important part of all this is that he worked out how to derive the system key. It simply grabs the user key from its new plain text keyring and can then decrypt/play the file.
ITUNES DRM CONVERTER CRACK WINDOWS
Then he grabs the now decrypted user keys, writes them off to disk in another file, and then Linux or Windows or whatever can play the songs without having to mess about. Using the system key, he can decrypt iTunes keyring file. Jon's hack works because he figured out how to derive the system key from the computer specific information. Using the user key for that song, it can decrypt the song, produce straight AAC, and play the thing. That local keyring contains the user keys for every account that this particular computer is authorized for.
So, when you play the song, iTunes grabs the computer specific info, uses this to build the "system key" which will decrypt the local keyring. Authorization works like this:Ī) iTunes reads the username from the songī) assuming you haven't authorized for that account already, iTunes contacts home base and asks you for your passwordĬ) iTunes downloads a copy of the user key from home base and stores it locallyĭ) however, the local keyring is also encrypted, using computer specific information like some registry keys, etc, etc. When you try to play a song, your copy of iTunes has to authorize itself. When you buy a song, a few things happen.Ī) the song gets encrypted using your user keyī) it gets stuck into an M4P wrapper which, among info about the song, contains the username for your account This account gets a "user key" assigned to it that is unique to the account. In order to buy tunes from iTMS, you have to get an account with Apple and get an "AppleID" which is basically just an email address for the username of the account. I know this is a bit late, but I just wanted to add this to the thread so that everyone has a better understanding of iTunes and the M4P's encryption.
0 kommentar(er)
