For amusement yesterday evening, I decided to take a closer look at what this 2048 bytes sized block of hash + 408 obfuscated disc keys actually looks like. Easiest way to do this was looking through the libdvdcss code.
So I went through more than a dozen dvd discs of various vintages from y2k to several years ago. (I don’t have any current 2018 movies on dvd). These were primarily american region1 releases. I only have a few region2 dvd discs, which I also checked.
Even without running any cracking code, it was obvious there were only around 33 unique obfuscated disc keys, where each unique obfuscated key was repeated around 11 or 12 times (except the hash and one key entry). I only found one disc which didn’t exhibit this specific repetition pattern, where this particular disc turned out to have 64 unique obfuscated disc keys with varying patterns of repetition. (This particular “anomalous” disc was a german release of a 90s era uk film, with a y2k date on the back cover).
I ran through the old Frank Stevenson code from 1999 which did the disc key crack on the hash, and another Frank Stevenson code which did this reverse engineering “generating” of the player keys. Lo and behold, 32 out of the 33 unique player keys from these dozen+ dvd discs were all identical on these dvd discs from y2k to around 2016/2017. (The 33rd key appeared to be a dud which didn’t return back anything on one disc, or returning back different possible reverse engineered keys which didn’t match at all between different dvd discs).
On the lone “anomalous” german y2k disc, 32 out of the 64 unique player keys were identical to the ones from the american region1 dvd discs I looked at. I have no idea what these remaining other 32 unique player keys were for.
The other few region2 specific dvd discs I checked, also had the same unique 32 player keys as the american region1 discs I looked at. I don’t have any dvd discs from other regions, which had css encryption.
I’m guessing after CSS was first cracked in late 1999, these 32 unique player keys ended up being “frozen in time” when the dvd licensing folks came to the realization that there was no point in changing/revoking player keys. My suspicion is that these 32 player keys were most likely specific to hardware standalone players which were already manufactured over 1997-1999.