Conditional Access System

What is CAS? In order to protect the content and rights, digital TV operators turn to the technology known as conditional access or CA. Conditional access, as the name itself suggests, provides the service of controlling the access to digital television to people who are or are not subscribers. Their end goal is simple and clear – encrypting the channel signal and decrypting it only for the viewers who meet the required conditions. Besides the most common use by digital TV operators, conditional access can also be applied to digital radio and data broadcasts, non-broadcast information and interactive services. The equipment and software required for the system is supplied by the CAS provider, so that the broadcasters can incorporate it in their own equipment. Every CA system is made up of the following fundamental components: a Subscriber Management System, a Subscriber Authorization System, a security module and a set-top box. Basics of CAS: When a broadcast equipment transmits encrypted data to the user, the set-top box filters these data signals and passes them to the security module. The security module checks the authorization status of the data received and, if authorized, decrypts the data and allows display to the user. CA systems use the Digital Video Broadcasting protocols such as SimulCrypt and MultiCrypt. SimulCrypt uses more than one set-top box, whereas MultiCrypt allows multiple CA systems to be used with a single set-top box containing a smart card for each CA system used. CA is implemented using a combination of scrambling and encryption techniques. A 48-bit secret key known as the control word is used to scramble the broadcast data, and this control word is changed frequently to avoid hacking. The control word is protected using encryption during transmission to the receiver as an entitlement control message. The CA subsystem present in the receiver’s set-top box can only decrypt the control word if it has been authorized to do so via an entitlement management message (EMM). An EMM is unique for each user and is identified by the user’s smart card. ****** Did you enjoy the video? If so, give it a like above! Subscribe to our channel for more techie video 👉 https://www.youtube.com/c/DeepakRai?sub_confirmation=1 Keep Learning!! Keep Growing!! P.S. Make sure to keep up with us by clicking the bell!