[linux-dvb] Re: Nova + PC Card(pcmcia) driver--is it possible to watch encrypted program by using these devices?

[<mocm@metzlerbros.de>]

Christian Limpach writes:
 > > >  Are you sure about that? AFAIK the CAM (the PCMCIA card) only returns
 > the
 > > > actual descrambler key (using informations found in the TS and in your
 > > > valid subscription card ofcoz'). You still need to descramble the
 > > > encrypted channel using this key (this is done outside the CAM - e.g. in
 > > > the AV711x on the rev1.3 card). And the algorithm you need here is
 > > > something you probably never can get... so the nova card + PCMCIA card
 > > > reader combination still misses an entity (the descrambler).
 > >
 > > No, you are wrong . The CAM contains a transport stream interface, to get
 > > the encrypted stream and return the decrypted stream. Please read the EN
 > > 50221 standard freely available at www.etsi.org .
 > 
 > 
 > Then either the standard is wrong or you misread it since this seems not to
 > be the case.  At least the software CI/CAM only sends the descrambler keys
 > to the DVB card and only needs the ECM PES as input, it never sees the
 > actual encrypted/decrypted data.  I don't know which part of the DVB card
 > does the descrambling, but there seems to be some relation between the
 > descrambler and the streams setup to be demuxed as DMX_PES_VIDEO/AUDIO on a
 > full card.
 > 

The ECD on the DVB card is never used in normal CAM operations. The
so-called software CAM is not a CAM, it is just an implementation of
the key descrambler.  The ECD on the DVB card is meant to be used with
a smartcard reader and a license and implementation of the respective
descrambling system (e.g. Viaccess, Conax, Irdeto etc.). This is done
in a variety of STBs, usually with Viaccess, which use the AV711x
chip.

Marcus




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