Cardsharing: Transferring DW Codes Over a Network

Hello colleagues! Like any normal person, I periodically take a break from work. And besides motorsports, I sometimes watch TV. Since the television provided via a conventional antenna does not suit me and I want HD , I chose satellite TV for myself. Having bought myself an inexpensive HD receiver, I lived with it without problems for about a year. But at one point, the number of televisions in the house was incremented and needed to be "repeated." I found out that there are several ways: or put a satellite converter with two outputs, buy a second receiver and pay for a second contract. Or use cardsharing technology. Out of habit, I went to Habr, to learn more about it, and did not find anything on this topic. Well, I’ll try to correct the situation and describe this technology.


As you know, getting access to satellite television doesn’t need so much: a satellite dish , a converter and a receiver . With this kit you can already catch the signal from satellites and watch TV. But, traditionally for any commercial system, the most interesting will be hidden. All channels of value are transmitted encoded . The most popular methods in Russia are Viaccess (NTV +) and DRE-Crypt (Tricolor TV).

The basic principle of these systems is the scrambling of the stream at the formation stage, followed by decryption on the client equipment. The key keeper is the operator’s smart card . The most important element is the Descrambling Words (abbreviated as “DW”), supplied by the card, which are used to decrypt the audio / video signal. Most systems transmit DW from the smart card in the clear, so there is the possibility of interception and transfer to another device.

Cardsharing is a technology that allows you to intercept DW codes and use them on other devices. Simply put, you can use the same smart card on multiple devices. The channel for transmission is usually a local area network or the Internet.

Of course, not every receiver is capable of becoming a cardsharing server. For this, specific receivers on the Linux operating system are used . The most popular of them are Dreambox . As customers, devices can be "simpler" class Golden Interstar and the like. I will not go into details of equipment settings, since this topic is pretty close to the “forbidden line”, but I would like to share with you a link that describes everything in an accessible way from the server point of view and from the point of view of the client . Do not forget only the main thing: change the default password to the root user .

In general, the issue of the legality of using this technology is relevant. Using it at home to broadcast on several televisions within the local network you violate the rules of use, but do not violate the law: one card is used only by this user in the same house. Unfortunately, I did not find any specifics in the legal aspect of card sharing at home.

But alas, not all users of this equipment have consciousness, and many tend to share key information for money. What is successfully done by our compatriots in huge numbers. Of course, this is already full-fledged piracy and is prosecuted by law.

Thank you for your time. Hope I told you something new.