You are right, in the sense that there are companies out there (I used to work for one of them) that do image, video and audio watermarking. In the simplest ter

You are right, in the sense that there are companies out there (I used to work for one of them) that do image, video and audio watermarking. In the simplest terms that's also adding imperceptible "noise" that statistically builds up to a few bits of data.