Suggestion for an alternative to watermarking and digital signatures

Watermarking consists of hiding of information within a multimedia element such as an image, a text, music or a video clip. Hiding information within other information is called steganography. A TV station’s logo may serve as an example for perceptible information. Steganographical methods are needed to integrate non-perceptible information: that means this information is hidden within a multimedia element like an image. Common operations like rotating, scaling, smoothing, sharpening, clipping, lossy compression or integration of hissing can destroy watermarks. The protection of a copyright on multimedia elements is one of the main uses of digital watermarks. All hidden information is protected by digital signatures which use an asymmetric key-pair to ensure security. The signed information is then integrated into the multimedia element as a non perceptible-digital watermark. A digital watermark is not sufficient for this task. In the presentation, the case of a preexistent database which contains objects describing the owner of a multimedia element and image’s features will be examined. A trusted party adds this information to an entry in its database and performs a hash over the data of the multimedia element. Additional operations will be performed to extract the main features of the multimedia element.