SECURE SPREAD SPECTRUM WATERMARKING FOR IMAGES, AUDIO AND VIDEO

We describe a digital watermarking method for use in au-dio, image, video and multimedia data. We argue that a watermark must be placed in perceptually significant com-ponents of a signal if it is to be robust to common signal distortions and malicious attack. However, it is well known that modification of these components can lead to percep-tual degradation of the signal. To avoid this, we propose to insert a watermark into the spectral components of the data using techniques analogous to spread sprectrum communi-cations, hiding a narrow band signal in a wideband channel that is the data. The watermark is difficult for an attacker to remove, even when several individuals conspire together with independently watermarked copies of the data. It is also robust to common signal and geometric distortions such as digital-to-analog and analog-to-digital conversion, resam-pling, quantization, dithering, compression, rotation, trans-lation, cropping and scaling. The same digital watermark-ing algorithm can be applied to all three media under con-sideration with only minor modifications, making it espe-cially appropriate for multimedia products. Retrieval of the watermark unambiguously identifies the owner, and the wa-termark can be constructed to make counterfeiting almost impossible. We present experimental results to support these claims. A longer version of this document is avail-able at