Abstract: Based on chaotic sequences and LWT (lifting wavelet transformation), a blind watermarking of color digital image algorithm protecting from shear transformation attack is given. Making use of feature of HVS, the watermark image is embedded into the color image’s low frequency component and middle frequency components by different means. The algorithm has highly security for using expanding frequency treatment and two kinds of chaotic mappings to scramble the watermark image. The algorithm has highly efficiency for using the LWT. Experiments indicate that the algorithm has high efficiency, strong robustness and security, and particularly it can protect from shear transformation attack.

Key words: computer application, blind watermarking algorithm, chaos sequences, LWT, protecting shear transformation attack