sslug-teknik team mailing list archive

[Niels Elgaard Larsen <elgaard@xxxxxxx>]

Martin Møller Skarbiniks Pedersen wrote:
> 2009/1/26 Michael Schmidt <michael.zmit@xxxxxxxxx>:
>> Hej NG
>> En af mine venner har opgivet at bruge sin (windows baserede) medie-PC til
>> afspilning af DVD film med forskellige regionskoder, da han siger at selve
>> drevet kun tillader at omskifte til ny kode et begræset antal gange.
>> Jeg har endnu ikke selv haf afspillet nogle af mine ikke-regionskode 2 eller
>> 0 film på PC'en, men er problemet det samme på en Linux baseret Media-PC?
>> - i så fald hvad skal der så til for at omgå begrænsningen?

Ifølge:
http://en.wikipedia.org/wiki/Regional_lockout

==
libdvdcss is capable of circumventing region codes on all RPC-1 DVD drives and the
majority of RPC-2 drives.
==

> Sig til din ven at han skal købe eller stjæle programmet anyDVD.

Kan han ikke bare bruge VLC til Windows:
http://www.videolan.org/vlc/

Det virkede i alt fald for mig for et par år siden da jeg havde bragt nogle danske DVD'er
til Canada og alt andet nægtede at spille dem.


Mplayer gør det på flg måde:
http://web.njit.edu/all_topics/Prog_Lang_Docs/html/mplayer/cd-dvd.html


==
DVD authentication

The authentication and decryption method of the new-style DVD support is done using a
patched libdvdcss (see above). The method can be specified through the environment
variable DVDCSS_METHOD, which can be set to key, disk or title.

If nothing is specified it tries the following methods (default: key, title request):

   1. bus key: This key is negotiated during authentication (a long mix of ioctls and
various key exchanges, crypto stuff) and is used to encrypt the title and disk keys before
sending them over the unprotected bus (to prevent eavesdropping). The bus key is needed to
get and predecrypt the crypted disk key.
   2. cached key: MPlayer looks for already cracked title keys which are stored in the
~/.mplayer/DVDKeys directory (fast ;).
   3. key: If no cached key is available, MPlayer tries to decrypt the disk key with a set
of included player keys.
   4. disk: If the key method fails (e.g. no included player keys), MPlayer will crack the
disk key using a brute force algorithm. This process is CPU intensive and requires 64 MB
of memory (16M 32Bit entries hash table) to store temporary data. This method should
always work (slow).
   5. title request: With the disk key MPlayer requests the crypted title keys, which are
inside hidden sectors using ioctl(). The region protection of RPC-2 drives is performed in
this step and may fail on such drives. If it succeeds, the title keys will be decrypted
with the bus and disk key.
   6. title: This method is used if the title request failed and does not rely on any key
exchange with the DVD drive. It uses a crypto attack to guess the title key directly (by
finding a repeating pattern in the decrypted VOB content and guessing that the plain text
corresponding to the first encrypted bytes is a continuation of that pattern). The method
is also known as "known plaintext attack" or "DeCSSPlus". In rare cases this may fail
because there is not enough encrypted data on the disk to perform a statistical attack or
because the key changes in the middle of a title. This method is the only way to decrypt a
DVD stored on a hard disk or a DVD with the wrong region on an RPC2 drive (slow).

RPC-1 DVD drives only protect region settings through software. RPC-2 drives have a
hardware protection that allows 5 changes only. It might be needed/recommended to upgrade
the firmware to RPC-1 if you have a RPC-2 DVD drive. Firmware upgrades can be found on
this firmware page. If there is no firmware upgrade available for your device, use the
regionset tool to set the region code of your DVD drive (under Linux). Warning: You can
only set the region 5 times.
==