"Unbreakable" watermark technology to debut

ACCORDING TO a recent article on the ZDNet wire, a new type of watermark technology developed by Stealth MediaLabs will soon be debuting that promises to change copying as we know it. Stealth's slogan, by the way, goes something like this: "Stealth MediaLabs' mission is to bring consumers of digital audio and video the best possible experience, by ensuring that media producers stay economically interested in creating compelling, exciting and valuable programming".

Now that we're all reassured by knowing our digital and audio experiences are in the best possible hands, let's examine the watermark technology Stealth is working on.

This new type of watermark technology is one that will remain encoded in a song, whether the music itself is digitally encoded, analog-recorded, or even recorded off the radio.

The watermark is embedded into the song itself as binary data which "[takes] advantage of acoustical properties and human hearing characteristics to make it imperceptible to the listener." I could be wrong on this - and feel free to correct me -- but I'm not sure how you pass binary data through an analog signal or through the radio, especially given that radio transmission noticeably degrades a signal anyway. Could a watermark signal be integrated into audio in such a way that it survived not only analog transmission but signal degradation as well?

Although initial plans for the new watermark are focusing on using it to prevent the ripping of review discs and preventing the music on them from being transferred to the 'Net early, the fact that so much redundancy is being built into this type of watermarking is concerning. Why bother to lock down radio transmission unless you feel it's a necessary part of a copyright protection system?

Even if we assume it's possible to encode a watermark system into a song without damaging the playback sound in any way, and that it can be transmitted with its protection intact over both radio and analog, what's to stop someone from writing software to filter out the protection sequence? The idea of using algorithms to filter data is nothing new—its how audio formats like MP3 or Ogg work. While systems like Macrovision can only be bypassed via a physical device that disables the copy protection, a computer has considerably more flexibility when it comes to its ability to edit, filter, and manipulate audio. In order to make such a watermark protect against any form of tampering, it would have to be impossible to write a computer program to de-filter the information.

Of course, such an action is illegal under the DMCA, but if the song information is scrubbed clean it shouldn't be possible to tell where it came from. The entire Stealth project would look like little more than another ill-fated attempt to develop a copy-proof system, save for the additional restrictions it places, or will attempt to place, on analog and radio output. Since when is recording songs off a radio restricted? One almost begins to wonder if record players and vinyl are about to come back into fashion. µ