Television encryption
From Biocrawler, the free encyclopedia.
Television encryption, often referred to as "scrambling", is encryption used to control access to pay television services, usually cable or satellite television services.
| Contents |
History
Originally, encryption was not used in pay television systems for controlling access to programming. Cable television systems have traditionally relied on controlling access by directly connecting and disconnecting the physical cable that provides programming from the subscriber's home to the actual cable network itself. Satellite television first began using encryption in 1986 when HBO began encrypting its signals.
Selective access
Cable and early satellite television encryption
Analog and digital pay television have several selective access systems that are used for pay per view (PPV) and other subscriber related services. Originally, analog-only cable TV systems relied on set-top boxes to control access to programming, as television sets originally were not "cable ready". Analog set-top boxes have largely been replaced by digital set-top boxes that can directly control access to programming as well as encrypt signals.
VideoCipher II RS (VCII RS) is the scrambling system that C-Band satellite pay TV channels originally used. A VCII-capable satellite receiver is required to decode VCII channels. VCII has largely been replaced by DigiCipher 2 in North America. Originally, VCII-based receivers had a separate modem technology for pay-per-view access known as Videopal. This technology became fully-integrated in later generation analog satellite television receivers.
- VideoCipher I (deprecated)
- VideoCipher II (deprecated)
- VideoCipher II+
- VideoCipher II RS (Renewable Security)
Digital cable and satellite television encryption
DigiCipher 2 is Motorola's proprietary video distribution system. DCII is based upon MPEG-2. A 4DTV satellite receiver is required to decode DCII channels. In North America, most digital cable programming is accessed with DigiCipher 2-based set-top boxes.
- DigiCipher II (digital, common usage)
PowerVu is another popular digital encryption technology used for non-residential usage. PowerVu was developed by Scientific Atlanta. Other commercial digital encryption systems are Irdeto (by Irdeto Access), Nagravision (by Kudelski), Viaccess (by France Telecom), and Wegener.
In the United States, both DirecTV and Dish Network direct broadcast satellite systems use digital encryption standards for controlling access to programming. DirecTV uses Videoguard, a system designed by NDS. DirecTV has the dubious distinction of being a relatively easy system to hack, which has led to an abundance of pirated access cards being available for that system. Dish Network uses Nagravision (1 and 2) encryption, which is thought to be a more secure encryption method.
In Canada, both Bell ExpressVu and StarChoice DBS systems use digital encryption standards. Bell ExpressVu, like Dish Network, uses Nagravision for encryption. StarChoice uses a DigiCipher 2-based system very similar to that of 4DTV large dish satellite systems.
Older television encryption systems
- Oak Orion
Oak Orion was originally used for analog satellite television pay channel access in Canada. It has been completely replaced by digital encryption technologies.
- Leitch
Leitch is an analog encryption standard used primarily by broadcast TV networks in the United States. It is only occasionally used today.
- B-MAC
B-MAC has not been used for DTH applications since Primestar switched to an all-digital delivery system in the mid-1990s.
- Viewguard
Viewguard Like VCII, the Viewguard system digitally encrypts video through the use of the cut and rotate method. The audio component of the satellite TV signal also is digitally encrypted.
External links
- rec.video.satellite.tvro FAQ (http://www.faqs.org/faqs/by-newsgroup/rec/rec.video.satellite.tvro.html)
