Watermarking Is Not Cryptography

A number of analogies to cryptographic concepts have been made about watermarking. In this paper, we argue that these analogies are misleading or incorrect, and highlight several analogies to support our argument. We believe that the fundamental role of watermarking is the reliable embedding and detection of information and should therefore be considered a form of communications. We note that the fields of communications and cryptography are quite distinct and while communications systems often combine technologies from the two fields, a layered architecture is applied that requires no knowledge of the layers above. We discuss how this layered approach can be applied to watermarking applications.