How to determine AACS verison

[Silasqwerty]

Hello! I want to find out what the AACS version of a disc is, and I tried searching here but I didn't see anything directly related to that. Is there any way to tell without using a program like MakeMKV? Or at least a program that documents how it detects the version.

[candela]

The version is in the AACS\MKB_RO.inf file

https://aacsla.com/aacs-specifications/
Introduction and Common Cryptographic Elements Book Rev 0.953 (PDF, 557 KB)
3.2.5.1.1 Type and Version Record

Or check aacskeys or Videolan's libaacs source code

[Silasqwerty]

Thank you so much!! I really do appreciate it:) One thing, the version reported by MakeMKV and aacsinfo (from https://forum.doom9.org/showthread.php?t=176924) doesn't always match what the specification said it should, for example I have a disc that according to MKB_RO.inf should be 42, but according to other software is 66. What's interesting to me is that earlier versions seem to match just fine, up to 7 seems to follow the specifications as expected. I will try to look through the sources of what you mentioned as well, but that will take me a little while to go through because I'm very new to coding.

[candela]

Thank you so much!! I really do appreciate it:) One thing, the version reported by MakeMKV and aacsinfo (from https://forum.doom9.org/showthread.php?t=176924) doesn't always match what the specification said it should, for example I have a disc that according to MKB_RO.inf should be 42, but according to other software is 66. What's interesting to me is that earlier versions seem to match just fine, up to 7 seems to follow the specifications as expected. I will try to look through the sources of what you mentioned as well, but that will take me a little while to go through because I'm very new to coding.

are you sure you are looking at
MKBv : X
and not at
Host Revocation List (MKB version Y):
in aacsinfo?

X is the inserted disc version, and Y is the highest version seen by aacsinfo so far and cached on your HDD

[Silasqwerty]

I'm sure. What aacsinfo reports as 66 is indicated as 42 in MKB_RO.inf, a 23 in aacsinfo as 17 in MKB_RO.inf, and a few others mismatch too. The ones I have that are versions 1, 2, 4, and 7 DO match MKB_RO.inf though. What aacsinfo reports also always seems to match what MakeMKV reports too. The "MKBType" as listed in the specs does match expected values so I seem to be looking in the right place. And as far as I can tell, all the other bytes dedicated to listing the version are empty, so there shouldn't be any other version information that I'm not accounting for.

[candela]

You are looking in hex editor? Of course it doesn't match, 42 hex = 66 dec, 17 hex = 23 dec

[Silasqwerty]

Oh hey thank you!! Of course it was something stupid of me like that, I really appreciate your help :) If you happen to know how to determine the BD+ version too, that would be amazing! Either way though, thank you again!

[candela]

Oh hey thank you!! Of course it was something stupid of me like that, I really appreciate your help :) If you happen to know how to determine the BD+ version too, that would be amazing! Either way though, thank you again!

There is no real version, there is a timestamp in BDSVM files that can be used to approximately date a certain generation of BD+ protection code.

https://forum.doom9.org/showpost.php?p=1403621&postcount=751

You need to check Videolan libbdplus source code how to read the timestamp, it's in bdsvm\loader.c