"A new watermarking technology could help track down people who make copies of copyrighted digital material. The technique works by concealing information about the identity of the offender inside the copy, according to the company developing the technique."

The upshot: UK company Amino Communications has commercialized a watermarking system with reasonably effective traitor tracing. But Microsoft's Fabien Petitolas (author of a good Artech House book on stego/watermarking) warns, "So far nobody has come up with schemes that are really robust to attacks."