From CAS to DRM, video content security paradigm has shifted and converged with multi-DRM and forensic watermarking

The origin of IPTV lies in the pay TV model of 1950s and 1960s, when video content owners and distributors wanted to maximize their revenue beyond advertisements. Stakeholders of the video content industry invented the conditional access system (CAS) to manage their users and offer them a variety of subscription plans. This technology allowed distributors to send encrypted video signals to users, which could be decrypted and played using set-top boxes (STBs).

With the arrival of digital videos, access control evolved into digital CAS in 1990s, which allowed even more finegrained control over content access and security to distributors. Digital video broadcasts (DVB) standards were codified into Common Scrambling Algorithm (CSA). The encryptions contained in the DVB standards could be called precursor to DRM protected content that has become the norm in the age of OTT content.

Despite the immense popularity of OTT platforms, pay TV continues to be popular in most markets. The OTT only households are still low in number. Therefore, distributors also depend on CAS and multi-DRM approaches to complement different arms of their business.

The character of STBs, which are used in CAS, has also undergone a change. Initially, distributors used cards to control access to video broadcasts. Howevers, as these devices evolved, system-on-a chip technology became popular that allowed decryption within the processing units of STBs.

Out of all the user management systems, multi-DRM technology is considered the most advanced one, especially when it is used with video watermarking technology. Most vendors provide multi-DRM and watermarking services as a unified service to content owners. The success of multi-DRM technology rests on the security it offers as a combination of software and hardware approach and the user of two-way communication facilitated by the internet, which makes verifying the user device in a dynamic scenario possible.

Even the DRM system has evolved further to be merged with STBs, especially for smart TVs. In scenarios where users depend on broadcast signals to watch their favourite channels, this type of hybrid model can add valuable information to their TV systems, like information about shows, show schedules, etc. and even offer recording options wherever the subscription plan permits it.