Created date

March 30, 2012

Content type (localized)



Musings from the Road: Evolution of Content Protection

A recent business trip took me through San Francisco International Airport, where I stumbled upon the Television: TV in the Antenna Age exhibit.  From my perspective, the most interesting part of the exhibit is the section on the evolution of screen sizes. 

The first black and white TVs in the 1920s had a screen size of about 4 inches. As the technology improved, screens grew to 10 inches, and later on to 20 inches. Then color TVs were introduced in the 1950s with a whopping screen size of 7 inches.  As technology continued to mature, screen size increased again to 20 - 30 inches.

As I was strolling through the exhibit, I was struck by the similarities between the evolution of TVs and mobile devices.  For example, do you remember when the first mobile devices started receiving TV streams?  Those mobile phones had a screen of three inches or so.  However, as the over-the-top (OTT) industry – or broadband TV industry as Jon Cody proposed at the OTTCON in Santa Clara last week - industry evolved, it had to invent tablets with seven to twelve inch screens and eventually connected TVs with 30, 40, 50, etc. inches.

It seems clear to me that history is repeating itself, or perhaps evolving in a spiral. Indeed, the same seems to be happening with content protection. We started with analog conditional access systems more than two decades ago, and evolved to digital conditional systems. As content value and quality increased, additional requirements for output control and copy protection were imposed by content owners.

We are seeing the same evolution in OTT (or broadband TV), which was initially underestimated and thus had no or very little content protection. But as the content quality (i.e., bitrate and resolution) and content value increased (full length movies, earlier release windows, etc.), the security requirements increased as well. Full-fledged CAS or DRM systems are required now, and as tablets and other portable devices start including digital outputs, HDCP will be also required.

This actually brings the security and robustness for OTT devices to the same level as for traditional set-top boxes. Even the hardware-assisted security that is already commonplace in many set top boxes (STBs) with secure system on chips (SoCs) is slowly being expected in mobile devices, sometimes in the form of a TrustZone implementation. In fact, this was the conclusion of our recent Content Security Requirements for Multi-Screen Video Services whitepaper, as well as of my recent talk at OTTCON .

Thinking about it a bit more, this approach makes sense – if the same content in the same quality appears on your good old STB in the living room, why should it be protected less on a portable device? And as a result, content protection technology is evolving as well. We are no longer limited to smart cards as an increasing number of software-based, cardless solutions emerge. Other techniques such as code obfuscation, code integrity checking, and white-box cryptography seamlessly augment hardware-based solutions. It appears that the industry is evolving and content protection is evolving alongside it.

What do you think?  What do you think is the next step in the evolution of content protection?  And if you’ve seen the history of TV exhibit at SFO, I’d love to hear your thoughts on that as well.