[vdr] encrypted channels - dumb question

Anssi Hannula anssi.hannula at gmail.com
Thu Oct 20 20:53:49 CEST 2005


I don't use encrypted channels myself, but I try to clarify some things
based on posts what I've read. I hope I don't give you any false

Simon Baxter wrote:
> Has anyone been able to get VDR working for encrypted channels?  Whether
> it be digital terrestrial, cable or satellite?

Many have. AFAIK the encryption system is identical in DVB-S/C/T, so it
doesn't matter.

> I'm not wanting to do anything illegal, but I would like to know how
> this works.  Some providers give you a smart-card, so I guess you'd need
> some kind of plug-in to allow validation of the 'key'.

You have to have a (supported) CI (Conditional Interface IIRC) in your
DVB card (or an interface in which you can buy the CI board separately,
as in FF DVB cards). In that CI interface you put a CAM (Conditional
Access Module IIRC) which you can buy yourself or sometimes get from
your provider. In that CAM there is a smart-card slot, where you
obviously put your smart-card.

The CAM uses smart-card and the broadcasted stream to generate some
"decrypt codes", whatever those are called. Those codes are then
transfered to a descrambler chip in the DVB card, which does the
decrypting of the broadcast stream.

If the user wants to subscribe/unsubscribe channels, the provider sends
the updated subscription information over the stream.

VDR doesn't require any plugins whatsoever for viewing encrypted channels.

> I've also had
> cable subscriptions where if you want another channel added, you phone
> the provider of your set-top-box and they enable something.  How does
> this work? Could this be done with a DVB-C VDR setup?

Well, you can only use subscriptions which have CAMs with VDR, and as
far as I know those are all smartcard-based.

Anssi Hannula

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