Conditional-access television broadcasting

in broadcast engineering

satellite signal scrambling system

television technology

230px|thumb|Nagra Kudelski Group logo Nagravision (or Nagra Kudelski or simply Nagra) is a company of the Kudelski Group that develops conditional access systems for digital cable and satellite television. The name is also used for their main products, the Nagravision encryption systems.

technology company

thumb|right|A Conax CAM module manufactured by SMiT Conax develops television encryption, conditional access and content security for digital television. Conax provide CAS technology to pay TV operators in 85 countries. The company has offices in Norway (headquarters), Russia, Germany, Brazil, the United States, Canada, Mexico, Indonesia, Philippines, Thailand, China, Singapore, and India, with a 24/7 Global Support Center in India.

PowerVu is a conditional access system for digital television developed by Scientific Atlanta. It is used for professional broadcasting, notably by Retevision, Bloomberg Television, Discovery Channel, AFRTS, ABS-CBN, GMA Network, and American Forces Network. It is also used by cable companies to prevent viewing by unauthorized viewers and non-cable subscribers.

thumb | right | Viaccess bays in the bottom half of the image Viaccess is a conditional access system developed by France Télécom, now Orange. There are six versions in use today, Viaccess PC2.3, Viaccess PC2.4, Viaccess PC2.5, Viaccess PC2.6, Viaccess ACS3.x/Prime Sentinel, Viaccess ACS4.1, Viaccess ACS5.0, and Viaccess ACS6.x/Adaptive Sentinel.

MediaGuard is a conditional access system for digital television developed by SECA (Société Européenne de Contrôle d'Accès; renamed to Canal+ Technologies SA) (CEO François Carayol), a subsidiary of Canal+ Group, sold to Thomson (CEO Thierry Breton). Then Canal+ Technologies SA was broken in two pieces by Thomson in 2003, the MediaGuard sold to Nagra France and the MediaHighway to NDS France.

right VideoGuard (sometimes referred to simply as NDS), produced by NDS, is a digital encryption system for use with conditional access television broadcasting. It is used on digital satellite television systems – some of which are operated by News Corporation, which owned about half (49%) of NDS until its sale to Cisco in 2012 (becoming Cisco Videoscape division). Since 2018 VideoGuard is improved and maintained by Synamedia (Cisco's spun-off company based on its former Videoscape division). Its two most widely used implementations are Sky in the United Kingdom and Ireland and DirecTV in the