Conditional-access module

[1] They are normally used with direct-broadcast satellite (DBS) services, although digital terrestrial pay TV suppliers also use CAMs.

NDS VideoGuard encryption, the preferred choice of Sky Digital can only be externally emulated by a Dragon brand CAM.

Dragon and Matrix, two popular cams with satellite television enthusiasts are Multicrypt meaning each is capable of handling more than one encryption system.

Although not officially supported or acknowledged, Multicrypt and programmable modules are a grey market in the pay-TV industry.

[citation needed] The primary purpose of the CAM is to derive control words, which are short-term decryption keys for video.