How a CableCARD Works

Let me first just say that if you are only interested in finding out whether or not you need a CableCARD, you can skip this section entirely. ;-)

As I mentioned, a CableCARD performs the same function as a set-top box. However, the decryption process when using a CableCARD is more complicated. Once the CableCARD receives the encrypted digital signal from your cable or satellite provider, there are three additional steps required before the video is displayed on your TV:

1) Decryption – The CableCARD receives encrypted digital programming information and decrypts it.

2) Re-encryption – The CableCARD then encrypts the decoded information again, and passes it on to the TV along with a decryption key.

3) Decryption – The TV receives the re-encrypted information and uses the decryption key to decrypt it.

Re-encryption is one way that cable providers prevent their services from being stolen. In order for the CableCARD to pass on the decryption key to your TV, it has to be activated by your cable or satellite provider. Activation is what tells the CableCARD that you've a legitimate customer and it is OK for you to be watching the channels that you subscribe to.