Difference between revisions of "Blu-ray"

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## The software player fails to read the disc content.
## The software player fails to read the disc content.
==== Decrypting using VUK (step 3.2.1) ====
==== Decrypting using VUK (step 3.1 or 3.2.1) ====
Using the VUK specific to your disc will always work, and cannot be revoked by the industry, as it is the most downstream decryption key for a Blu-ray disc. However, there is one unique VUK per disc, corresponding to one VID, making this method rely on VUK lists or databases. The VUK will be known if either of these are true:
Using the VUK specific to your disc will always work, and cannot be revoked by the industry, as it is the most downstream decryption key for a Blu-ray disc. However, there is one unique VUK per disc, corresponding to one VID, making this method rely on VUK lists or databases. The VUK will be known if either of these are true:

Revision as of 13:40, 11 December 2015

Tango-edit-clear.pngThis article or section needs language, wiki syntax or style improvements.Tango-edit-clear.png

Reason: please use the first argument of the template to provide a brief explanation. (Discuss in Talk:Blu-ray#)

This article is designed to help Linux users to play the BluRay discs they have legally purchased on their computers. Since no official BluRay player software is available on their system, Linux users have to use open-source libraries capable of handling the DRM schemes that protect these disc contents. This is legal in most countries where interoperability allows this.

How it works

Blu-ray DRM

Contrary to the DVD CSS, which was definitely compromised once the unique encryption key had been discovered, BluRay uses stronger DRM mechanisms, which makes it a lot more difficult to manage. Firstly, the AACS standard uses a lot more complicated cryptographic process to protect the disc content, but also allows the industry to revoke compromised keys and distribute new keys through new BR discs. Secondly, BluRay may also use another layer of protection: BD+. Although most of commercial discs use AACS, a few of them additionally use BD+. In 2007, the AACS system was compromised and decryption keys were published on the Internet. Many decryption programs were made available, but the interest to Linux users was the capability of playing their discs - legally purchased - on their computers. Although the industry was able to revoke the first leaked decryption keys, new keys are regularly published in a cat and mouse play.


The AACS specification and decryption process are publicly available at [1]. Many articles and research papers describe it in detail at [2], [3] or [4].

libaacs is a research project from the VideoLAN developer team to implement the Advanced Access Content System specification, and distributed as an open-source library [5]. This project does not offer any key or certificate that could be used to decode encrypted copyrighted material. However, combined with a key database file, it is possible to use it to play BluRay discs that use the AACS standard. This file is called KEYDB.cfg and is accessed by libaacs in ~/.config/aacs. The format of this file is available at [6].

AACS decryption process

The AACS decryption process for a protected disc by a licensed player goes through four stages:

  1. The software/embedded player's Device Keys, together with the disc's Media Key Block (MKB) data are used to retrieve a "Processing Key", and with that (plus another datum from the MKB) to compute the Media Key.
  2. That Media Key, together with the disc's Volume ID (VID) obtained by the player presenting a valid Host Certificate to the drive is used to compute the Volume Unique Key (VUK).
  3. This VUK is used to unscramble the disc's scrambled Title Keys.
  4. Finally those Title Keys unscramble the disc's protected media content.

Note that it is the disc that contains the MKB. MKB have been renewed since the first commercial BluRay release in 2006. The latest MKB is version 30, but many MKB actually share the same key. The software player provides the Host key and certificate, whereas the drive contains a list of the Host key/certificates that have been revoked.

Using libaacs, the decryption process can skip some of these stages to reach the last step, which allows the media player to play the disc. This is either by providing in the KEYDB.cfg file either (or both):

  • a valid (corresponding to the MKB version of the disc) Processing key and a valid (i.e. non revoked by the drive) Host key/certificate
  • a valid VUK for the specific disc.

If libaacs finds a valid processing key for the disc MKB version as well as a valid Host key and certificates, it can start the decryption process from step 2. However, the Host key/certificates are regularly revoked through the propagation of new BluRay discs. Once revoked, a drive is not able to read both new and older discs. This is usually irreversible and can only be fixed by providing a more recent Host key/certificate (for Windows users, this corresponds to updating their software player). The advantage of this method is that until the Host key/certificate is revoked, and as long as the disc uses an MKB version for which the Processing key is known, libaacs is able to compute the VUK of any disc. As of today, the Processing keys for MKB versions 1 to 28 have been computed and made available on the Internet.

Thankfully, in case no valid Processing key is available and/or the Host certificate has been revoked, libaacs has an alternative way to decrypt a disc: by providing a valid VUK in the KEYDB.cfg file. This allows libaacs to skip directly to step 3. Contrary to the Processing keys, VUKs are disc specific. Therefore this is less efficient as the user will have to get the VUK from a third party. But the great advantage is that VUKs cannot be revoked. Note that if libaacs is able to perform step 2 (with a valid Host key/certificate), then it stores the VUK calculated in step 3 in ~/.cache/aacs/vuk. At subsequent viewings of the same disc, libaacs can reuse the stored VUK. Thus it may be a good idea to backup these VUKs.

There have been several efforts to compile VUKs from various sources. Early attempts include forum threads, such as available at: http://forum.doom9.org/attachment.php?attachmentid=11170&d=1276615904 or http://forum.doom9.org/showthread.php?p=1525922#post1525922. Recently, a centralised VUK database has been made available at [7], with more than 11000 published VUKs. This is the most comprehensive source of public VUKs available.


BD+ is an additional but optional component of the Blu-ray DRM. In December 2013, VideoLAN released the long awaited libbdplusAUR which provides experimental support for BD+ decryption. The library does not provide keys or certificates required for BD+ decryption, you need to retrive and install them separately, as explained at [8] and [9].



  1. install libbluray and libaacs from the official repositories.
  2. Download the KEYDB.cfg file from [10] and copy it in the directory ~/.config/aacs. This file contains PK, HC and VUK data required for attempting the decryption process described below for nearly 12000 discs.
  3. If necessary (i.e. if volumes are not mounted automatically on your system), mount the bluray to a directory, e.g.:
    # mount /dev/sr0 /media/blurays

Decryption process

Launch a Blu-ray software player, such as VLC, and try to play the disc (on VLC, select Media -> Open Disc, then in the Disc tab, chose Blu-ray. Be sure "No disc Menus" is checked.). The software player will then apply the decryption process described below:

  1. The user starts playing a BluRay with a video player having libbluray and libaacs support.
  2. If the BR disc is not scrambled with AACS, go to 4.1.
  3. If the BR disc is scrambled with AACS, libaacs will:
    1. Check if a valid VUK for the disc is already available in ~/.cache/aacs/vuk/. If yes, go to step 4.1, if not continue to next step.
    2. Read ~/.config/aacs/KEYDB.cfg:
      1. If a valid VUK is available, go to 4.1, if not continue to next step.
      2. If a valid Processing key (i.e. corresponding to the disc MKB version) and a valid (non-revoked by drive) Host key/certificate is available, libaacs will compute the VUK. The VUK is stored in ~/.cache/aacs/vuk for future use. Go to step 4.1.
    3. If no valid key is available, go to step 4.2.
  4. Result
    1. The software player is able to play the disc content.
    2. The software player fails to read the disc content.

Decrypting using VUK (step 3.1 or 3.2.1)

Using the VUK specific to your disc will always work, and cannot be revoked by the industry, as it is the most downstream decryption key for a Blu-ray disc. However, there is one unique VUK per disc, corresponding to one VID, making this method rely on VUK lists or databases. The VUK will be known if either of these are true:

  • decrypting using PK and Host K/C described below has worked once, and the generated VUK for your disc has been stored in ~/.cache/aacs/vuk, or
  • the valid VUK for your disc has been obtained from a third party (e.g. is available in the . This allows you to read a disc, even if the PK and host key/certificate have been revoked for your disc MKB version.

If none of these are true, then the software player will attempt decrypting the disc using the second method.

Decrypting using PK and Host K/C (step 3.2.2)

The advantage of this method is that - when it works - it can decrypt any disc (up to a certain MBK version) and compute the VUK required to play it. Once the VUK is known, it is then stored for future usage.

Note: As of December 2015, latest commercial Blu-ray discs come with MKB v56. Incidentally, Method 1 has been obsolete for quite a long time. The method is presented for information purpose, but has little chance to be used with recent discs until newer PKs are made available. Therefore, Method 2 is now privileged, since it is irrevocable by the movie industry. However, this implies Linux users rely on discovery by third parties since there is no more any open source tool on Linux that can generate VUKs for discs with MKB v29 and above.

This method uses the Processing keys and a Host key/certificate present at the beginning of the KEYDB.cfg file. Currently, they will work for a disc up to MKB v28 but have been revoked in MKB v30 and above discs) in ~/.config/aacs/. Further, this method will only work if your drive has not revoked the host key/certificate that is in this KEYDB.cfg file (i.e. if you have not tried to play a disc with MKB v30 and above).

If this method is successful, after you play the disc, libaacs will store the VUK in ~/.cache/aacs/vuk. The filename is the disc ID and its content is the VUK itself. VLC will reuse this VUK even if it does not find a valid KEYDB.cfg file, so it could be a good idea to backup this directory for the future.

PK, VUK and BD+ support

These pages [11] and [12] provide you with keys and instructions on how to play Blu-ray discs using free software players. Hopefully the efforts of the maintainer of this website will help users play their Blu-ray discs in an easy way.

Media players

These are media players capable of using libbluray and libaacs to play AACS-scrambled BluRay discs.


To play blurays in mplayer the basic playback command is:

$ mplayer br:///</bluray/mount/dir>


$ mplayer br://<title number> -bluray-device </bluray/mount/dir>
Stuttering video

It is likely that you will need to enable hardware acceleration and multi core CPU support for the bluray to play smoothly.

For nvidia cards, enable hardware acceleration by installing libvdpau and using the option '-vo vdpau' with mplayer. e.g:

$ mplayer -vo vdpau br:///</bluray/mount/dir>

For multi core CPU support use the options '-lavdopts threads=N', where 'N' is the number of cores, e.g:

$ mplayer -lavdopts threads=2 br:///</bluray/mount/dir>
Incorrect audio language

You can scroll through the playback languages using the '#' key.

Out-of-sync audio

From your first mplayer output, you must find the codec used for the bluray. It will be at the end of the line "Selected video codec".

For H.264 discs use the option '-vc ffh264vdpau'. e.g:

$ mplayer -vc ffh264vdpau br:///</bluray/mount/dir>

For VC-1 discs use '-vc ffvc1vdpau'. e.g:

$ mplayer -vc ffvc1vdpau br:///</bluray/mount/dir>

For MPEG discs use '-vc ffmpeg12vdpau'. e.g:

$ mplayer -vc ffmpeg12vdpau br:///</bluray/mount/dir>


Since version 2.0.0, vlc has had experimental bluray playback support. Bluray menus can be used if you install libbluray-gitAUR instead of libbluray.

Start playback with:

$ vlc bluray://</bluray/mount/dir>


Start playback with:

$ xine bluray://</bluray/mount/dir>


Absent KEYDB.cfg file

If a valid VUK is found in ~/.cache/aacs/vuk, then libaacs does not need to use KEYDB.cfg to decrypt the content. However, a KEYDB.cfg file in ~/.config/aacs/ is still required (even if that file is empty).

Revoked Host key/certificate

Unfortunately, what may happen when trying to play a newer BluRay disc is the revocation of host key/certificates (which are keys of licensed software players) by your drive. When this happens, aacskeysAUR will return this message:

 The given Host Certficate / Private Key has been revoked by your drive.

This is part of the AACS protection scheme: editors are able to revoke old software player host keys that have leaked on the Internet and distribute the lists on newer commercial disc releases. This is irreversible and does cannot be fixed even after reflashing the drive. The only two ways to correct this would be:

  • to update the host key/certificate part in KEYDB.cfg to ones that have not been revoked (yet)
  • to add in KEYDB.cfg the VUK of each specific disc instead, as explained above. VUKs cannot be revoked by the industry.

When a disc (using mplayer or vlc) is succesfully decrypted, libaacs will store the VUK in ~/.cache/aacs/vuk. If the host key/certificate in KEYDB.cfg is subsequently revoked, VLC will still be able to use the stored VUK, so it could be a good idea to backup the ~/.cache/aacs directory for the future.

Using aacskeys

Install aacskeysAUR. You need to run aacskeysAUR from a directory that contains valid host key/certificate and processing keys:

cd /usr/share/aacskeys
and run:
aacskeys </bluray/mount/dir>
cd /usr/share/aacskeys && aacskeys /media/blurays

If you wish, you may add the BR to the key database: edit ~/.config/aacs/KEYDB.cfg and add the information output by aacskeys using this syntax:

0x<unit key file hash> = Film Title    | V | 0x<volume unique key>
If aacskeys is not able to generate the key

Try to generate the VolumeID with DumpVID using wine. The VolumeID can now be used to generate the bluray key with aacskeys with the VolumeID option

Usage: aacskeys [options] <mountpath> [volume id / binding nonce]

See also

For DVD, the libdvdcss package supplies the needed decryption libs. Below are some options for BluRay/HD-DVD decryption. Users can employ to backup a commercial BluRay movie under Fair Use guidelines:

  • anydvdhd - Commercial software requiring users to run it on an Microsoft OS in a VM.