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AACS versions and revisions

Posted: Wed May 23, 2018 9:42 pm
by mike admin
Here is a list of known AACS versions and some technical notes on them. All names are "official", that's how they are referred in documentation / software.

AACS 1.0 - currently used on all Blu-ray discs
AACS 1.0/Class II - documented publicly, never used on any discs.
AACS 2.0/Category C - evolutionary improvement of AACS 1.0, used on UHD discs.
AACS 2.1/Category C - same as Class II to AACS1.0 - First used on UHD Fury and Patriot on 22.05.2018
AACS 2.x/Category B - never used so far
AACS 2.x/Category A - never used so far

Key-wise 1.0, 2.0 and 2.1 are independent - with the same MKB version the same device can be revoked in one AACS branch and be non-revoked in another. For example a device can be revoked in v61 AACS 2.0 MKB but can be live in 1.0 v61 and 2.1 v61. Any combination is possible.

In AACS 2.x the "decryption" process (by a player) is rather different from AACS 1.0 - compliant device not only decrypts the content but also actively meddles with it. Forensic mark is always inserted into video stream at the decryption layer. This mark contains player model and serial number along with environmental details. This information is preserved in video stream and survives screen / HDMI capture.

Current MakeMKV status:
AACS 1.0 - fully supported
AACS 2.0/CatC - supported with external (hashed) keys
AACS 2.1/CatC - supported from version 1.14.6

Regardless of protection MakeMKV is able to make a non-decrypted full disc backup. This backup is as good as original disc, should the protection be supported in future.