A novel semi-private watermarking technique

A novel watermarking technique is proposed to embed a semi-watermark in digital images. Before embedding the watermark, a M-dimensional vector is extracted from the original data. Watermarking is achieved by modifying this vector to another particular vector according to the private keys and the watermark. A dual-key system is used to reduce the chance for the removal of watermark. The watermark can be detected without the original image. If the original image is available in the detection of watermark, the proposed technique is almost equivalent to the well known spread spectrum technique.