Freecardsharing Exchange of cards, also known as exchange of "control" a method is known that several clients or digital television sets allows a subscription television network with only one membership card to access valid. This is by electronic means as a legitimate part of the Conditional Access smartcard achieve data output, so that all recipients simultaneously access to encrypted DVB streams, which began in the encrypted network television. Typically, a smart card, a legitimate host of digital television, which is equipped with software to decode associated control word shares 64-bit "key on a computer network like the Internet. After the client receives decrypt this key, the encrypted content, as if they were using their membership card.

Free Card sharing has established itself as popular method of pirate decryption. Much of the development of card sharing hardware and software has taken place in Europe, where national boundaries mean that home users are able to receive satellite television signals from many countries but are unable to legally subscribe to them due to licensing restrictions on broadcasters.

Because the length of the control word is so small (typically 64 bits), delivery of the control words to many different clients is easily possible on a home internet connection. This has sparked the creation of sharing network groups, in which users can access the group by sharing their subscription cards with the group, and in turn, being capable of receiving the channels which all users' cards can decrypt, as though the user owned every single subscription card connected to the network. Other networks have also been created, whereby one server has multiple legitimate subscription cards connected to it. Access to this server is then restricted to those who pay the server's owner their own subscription fee.