Large-capacity Fragile Watermarking Scheme for Color Images Based on Prime Number Distribution Theory

Color image digital watermarking technology is an important security protection technology to realize secret communication and content authentication. To better achieve the purpose of color image copyright protection, this paper proposes three watermark embedding schemes for color images based on the prime number distribution theory, embedding the RGB three channels of the color carrier image into binary watermark images of the same size to realize large-capacity watermark embedding. The scheme uses the Rivest Cipher 4 (RC4) encryption algorithm to securely encrypt the image information. During the watermark embedding process, the appropriate pixel value is selected for pixel replacement according to the division of the prime number set within 0-255. The experimental results show that the PSNR values of the three schemes are all greater than 40dB, and the NC values are all close to 1. Compared with the existing algorithms, the scheme proposed in this paper has a large embedding capacity, which can resist common image processing attacks while ensuring good imperceptibility of the watermark, and has good tamper detection and localization capabilities.