Robust Zero-Watermarking Algorithm for Medical Images Based on AGAST-LATCH and DCT

Medical image transmission is an important aspect of digital healthcare. However, security and privacy are crucial issues during this process. Traditional watermarking techniques have become unreliable due to the damage they cause to pixel information in images. To solve this problem, zero-watermarking technology has emerged. Compared to traditional watermarking technology, zero-watermarking does not affect the visibility and quality of medical images and has higher robustness against attacks. Based on this, a robust zero-watermarking algorithm for medical images based on AGAST-LATCH and DCT is proposed in this paper. First, the AGAST algorithm and LATCH algorithm are combined to extract the feature matrix of the medical image. Then, the hash sequences of the medical image are obtained using Discrete Cosine Transform (DCT) and perceptual hashing algorithm on the feature matrix. The resulting hash sequence is combined with the encrypted watermark information, which is encrypted by the chaotic state of Logistic Map to enhance the robustness of the watermark information. Finally, a zero-watermarking technique is employed to create a watermark that is resistant to both conventional and geometric attacks.