What is a digital watermark?
A digital watermark is, in essence, a hidden message, within a digitized image, video or audio recording. The watermark is integrated into the content itself, so it requires no additional storage space. It can contain any information that the party writing the watermark cares to embed into a given work. Practically speaking though, space is at a premium, so the embedded message is usually quite small, often a short number. However that identifier can be mapped to any other kind of information – the composer’s name, the studio musicians who recorded his composition, or the name and e-mail address of the consumer who purchased a copy of the recording. Unlike a traditional watermark on paper, which is generally visible to the eye, digital watermarks can be made invisible or inaudible. They can, however, be read by a computer with the proper decoding software.
