Conditional access systems (CAS) in STB

There are STB for viewing only uncoded channel (Free to Air — FTA), as well as with the support of different conditional access systems (CAS). Rather a great amount of such systems are currently represented on the market of digital broadcasting. The most popular among them are VIACCESS, IRDETO, CONAX, MEDIAGUARD and NAGRAVISION. Regional conditional access systems are worth noticing as well. They have become widely used in the CIS: CryptOn, DVCrypt, NordE, MSA, DRE.

For most end users of digital telecommunications systems, CAS embodied in the form of smart cards or CAM-modules (Conditional Access Module), which are inserted into the appropriate STB slot and allow the user to access a variety of information services: TV channels, radio, Internet resources, teleconferences, "video on demand" (VoD), etc.

Promwad’s engineers use two different technologies for a conditional access implementation in STB:

CAS implementation with Conditional Access Module

Conditional access support implementation using CAM (Conditional Access Module) and CI (Common Interface).

STB Conditional access system with external CAM
Picture 1. STB Conditional access system with external CAM

Scrambled transport stream is sent to external CAM, being decoded and sent to decoder.

Promwad realized and tested a software stack by EN 50221 standards with the following CAM modules: Conax, Irdeto, DRE, Viaccess, XCrypt.


CAS implementation in STB

Conditional access systems integration into set-top-box software.

Picture 2. Conditional access system in STB with embedded descrambler and external smartcard
Picture 2. Conditional access system in STB with embedded descrambler and external smartcard

Descrambling is implemented by embedded hardware descrambler. An external smartcard for decryption keys is used (supplied by service provider).

The following systems were successfully integrated by Promwad’s engineers:

Integration is made by STB software engineering according to the requirements of a conditional access system provider. After software implementation a testing procedure is being lunched to prove compliance with the system requirements. Next step is a certification of STB by CAS provider.



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