Hi!

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 information.

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.

Damien Bally a écrit :

Hello

As far as I know there is a plugin named sc (softcam) that allows someone to view encrypted channels. Can anyone explain the way it works ? Don't misunderstand me : I don't want an howto to do something illegal, just some theory to satisfy my curiosity.

SC replaces the hardware CAM, when you have a budget card with no CI (connector for the CAM). It can be a fully software CAM, or use a smartcard reader to use the subscription card you have. Another missing part in common budget card is the descrambler chip, which can be replaced by a software one. The scrambling algo is called CSA (common scrambling algorithm). I don't know what can be considered illegal there, except when you do not use a valid subscription card. There is less in all this than in DeCSS, which includes keys (ie. smartcard) + key management (ie. SC) + algo (ie FFdeCSA).

The theory behind that is roughly : * the stream contains information about key management algo * it also contains random bytes (like a public key) * the CAM must use one of it's internal key management algo, along with those bytes, to select the appropriate private key inside the smartcard * it then transmits the key to the descrambling chip, that does the actual descrambling * the whole process is repeated at each channel change, and also from time to time, I think

I hope I didn't upset anyone with that...

Lars Bläser lars.blaeser@lycosxxl.de wrote:

the problem is the local law, in germany something like this (maybe) could be seen as a description how to brake the protection and will be illeagal - afaik nobody was yet prosecuted in germany for something like

The wording in §95ff is very weak - what exactly is "effective" ("wirksam")? I doubt this been tested before a court yet. Could go wrong to some extent depending on the judges.

Don't want to start a meta discussion here, though.