Abstract:Given the poor robustness and low security of traditional watermark-based copyright protection of digital images, a zero watermarking algorithm based on multiple features and chaotic encryption is proposed to improve the differentiability of the zero watermarks of different images. Specifically, global and local perspectives are utilized to extract the five-dimensional features of the image, including its mean feature, variance feature, skewness feature, kurtosis feature, and histogram of oriented gradients (HOG) feature. Then, the watermarked image is encrypted by the proposed block scrambling method based on chaotic mapping. Finally, zero watermarking information is constructed with the multiple features extracted and the scrambled watermarks. The copyright authentication process starts by extracting the multiple features. Then, the encrypted watermarks are obtained according to the zero watermarking information and decrypted, thereby achieving copyright authentication. The experimental results show that the proposed method has high efficiency, high security, and strong anti-attack capability. Integrating various properties of the digital image as the features, the proposed zero watermarking algorithm based on multiple features and chaotic encryption is stable and more robust. In addition, the proposed block scrambling method based on chaotic mapping improves the security of the watermarked images. The proposed algorithm and method effectively solve the problems of the poor robustness and low security of image watermarks.