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The Difference between CA and DRM

9/05/2009 2:00 AM Eastern

The clutter of language continues to grow, as another major distribution passageway shoulders up against its predecessors for attention.

That'd be IP (Internet-protocol) video transport. The lane that serves anything that wants an Internet connection, and soon enough a broadband Internet connection.

Like any other new way of moving video — after all, we are 61 years into this trajectory — there are three main obstacles any cable operator faces, when crafting it into a service.

One is the billing system. Another is the guide, or, in today's parlance, the “user interface.”

Third is the security. In the current chapter — linear digital TV, in standard- and high-definition — people tend to call this “CA,” for “conditional access.” On the condition that your cable video account is in good standing, you may access the video.

In the looming IP-video chapter, these activities are largely bundled under the term “DRM,” for “digital rights management.”

So the surface-level explanation of the difference between CA and DRM is this: CA is today, DRM is tomorrow.

But that would ignore the storied history of signal protection in cable, which has many, many chapters. Way back in the days of analog TV, there was mid-band tuning, negative traps, positive traps, sync suppression, interdiction, and addressable scrambling. And that's a partial list.

Then came digital, which added “encryption” — the digital version of scrambling.

And now, DRM.

Here's what changes: DRM (surprise, surprise) is software-based, meaning it doesn't require a dedicated security chip inside the display device. CA, by contrast, is a core purpose of digital set-top boxes and CableCards.

The very stuff we call “CA” today morphs to “entitlements,” in the IP video world. If your accounts are in good standing, you're entitled to view a title on whichever screens. Not just the TV.

To that end, CA ties to transport, while DRM attaches itself to the “asset” — the thing you want to watch.

DRM is but one example of transitional tech language, and there's a flood of it coming. We'll keep the translation machine tuned.

Stumped by gibberish? Visit Leslie Ellis atwww.translation-please.com.

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