The Impossible Dream

Sanyo’s HDTV camcorder, using advanced video compression and SD Memory Card storage, has a suggested retail price under $800. Congress is considering authorizing the FCC to create a content-protecting “broadcast flag.” Is there a connection?

The National Security Agency has been in the news recently, but not for its National Cryptologic Museum, a shrine to information security. Within the museum’s walls are not only the data-encrypting World War II Enigma machine, but also an 18th-century device referred to as Jefferson’s Cipher Wheel, the oldest existing transmission-protection mechanism, and a book on encryption published in 1518.

Of course, the concept is even older. For almost as long as there has been communication, there has been a desire to control access to it.

Today, much of the global economy is based on information security. Credit cards, ATMs and bank transfers all require—and use—secure data communications.

Digital audio and video signals are simply streams of bits, just like bank data. They may be secured using similar encryption techniques—or less.

Some early cable TV premium programming was “protected” simply by transmitting it on channels to which ordinary TV sets couldn’t tune. As Bob Cooper’s fascinating new book Television’s Pirates ( points out, early satellite transmissions were considered secure simply because no one had dishes; it was the so-called pirates who created the home satellite industry.

Since those early days, conditional access protective techniques have grown more elaborate. Although there are still news reports of “pirates” enabling unauthorized access to television programming, the pay TV industry has record revenues.

Now, however, content owners and providers want to restrict not only access to their programming but also what can be done with it. The FCC tried to codify their desires in a “broadcast flag,” an indicator of whether retransmission consent is freely given or withheld.

If withheld, a viewer would still be able to watch and listen to the show via secure digital connections, but the content-protection mechanisms of those connections would have to be able to prevent its being released where its rights holders don’t want it to be, the worst-case scenario being free distribution on the Internet. The FCC was so concerned about the unauthorized redistribution of digital content that the broadcast flag order required manufacturers to restrict access even to internal wiring. The connection between a demodulator chip and a decoder chip had to be made inaccessible even to a consumer equipped with tools.

Aside from cost to manufacturers and inconvenience to consumers, there were a few problems with the content protection aspect of the broadcast flag. One was that a court determined that the commission didn’t have the authority to order it, something that Congress might change soon. Another problem was the many unprotected digital-television devices already in homes. Yet another was what would happen to analog connections.

Many HDTV viewers have only analog inputs to their displays. If analog inputs are not protected, however, then an analog-to-digital converter can create an unprotected digital signal. Such concerns led to the image constraint token in next generation consumer disk players, which, if used, can reduce the resolution of analog outputs or eliminate them altogether.

Given the high quality of today’s HDTV upconverters (Let It Wave showed a new type based on bandlet processing at NAB2006) and the low quality of most displays, it’s unclear that restricting analog resolution will do much to dissuade retransmission. But there’s an even easier way to capture content.

When the modern era of in-room hotel movies began in 1971, one of the pioneering companies, Computer Television, captured such movies as Butch Cassidy and the Sundance Kid, M*A*S*H and Tora! Tora! Tora! by aiming a video camera at a film projected on a screen. So, when, a few years later, the company’s director of operations and engineering spoke at a content-security conference, he asked what was to stop a pirate from simply aiming a camera at a screen, and a collective gasp rose from the assembled.

That was at a time before VHS and, effectively, before home video cameras. Today, there’s Sanyo’s VPC-HD1, an under $800 HDTV camcorder using advanced encoding.

Nothing in the FCC’s old broadcast flag order technically prevented anyone from aiming an HDTV camcorder at an HDTV screen. The proposed Congressional authorization of a broadcast flag won’t stop it, either.

The First Law of Information Security: anything visible is stealable.

Mark Schubin is an engineering consultant with a diverse range of clients, from the Metropolitan Opera to Sesame Workshop.