Microsoft Granted “Stealthy Audio Watermarking” Patent
Microsoft was just awarded a patent for stealthy audio watermarking, a digital-watermarking technology for use in non-DRM digital music files.
The technology embeds a unique identifier into a digital music file, which can then be detected for identifying the copyright holder. According to a filing with the U.S. Patent and Trade Organization (USPTO), the watermark “cannot be removed,” although I’m sure some hackers will do their best.
The application for U.S. patent 7,266,697 was filed May 3, 2004, by Darko Kirovski and Henrique Malvar, both of whom work at Microsoft Research. Digital watermarking technology doesn’t encrypt files like Microsoft’s own Windows Media DRM does or prevent illegal filetrading, but it can be used to prove who purchased the digital file by embedding a unique digital signature. In other words, illegally traded songs could be tracked back to the original purchaser, allowing the RIAA to identify copyright infringers in a more sophiscated manner.
Not only is Kirovski and Malvar’s stealthy audio watermarking inaudible, but they are “scattered throughout the file in such a way that they cannot be identified and manipulated.” By distributing the watermark randomly in the audio file, it will prevent it from easily being stripped out by hackers and be robust enough so that it can withstand major modifications to the file.
The Future: Down the road, the technology could also be used to track files for royalties in new music distribution models.