On digital watermarks based on complete complementary codes

Digital watermarking technologies with spread spectrum (SS) sequences have been previously proposed. The sequences used in previous studies, however, do not necessarily have good correlation properties. It is known that complete complementary codes have ideal correlation properties and very effective for mobile communication systems like CDMA. In this paper, it is shown that correlation properties of sequences play very important roles in detecting the embedded secret information from the watermarked images. In addition, we propose a method to embed multiple secret data simultaneously into a single image.