A Novel Robust Watermarking Algorithm for Encrypted Medical Images Based on Non-Subsampled Shearlet Transform and Schur Decomposition
Meng Yang, Jingbing Li, Uzair Aslam Bhatti, Yiyi Yuan, Qinqing Zhang · 2023
Digital watermarking has evolved since its inception. In the sphere of medicine, zero watermarking technology has been used continuously in recent years. Patients&s; privacy is protected by embedding patients&s; personal information or diagnosis results into medical images in the form of digital watermarking. To guarantee the security of the watermark information, encryption technology is usually adopted in this process to encrypt the watermark information that will be embedded. However, in the process of network communication, original medical images that include personal information about patients also has information security risks when attacked. To deal with this issue, we propose a novel robust watermarking algorithm for encrypted medical images based on Non-Subsampled Shearlet Transform and Schur decomposition. Firstly, the security of the carrier medical image information is improved by encrypting it using a combination of tent chaotic sequence under DWT-DCT transform domain. Then, the NSST-Schur transform is applied to the encrypted medical images, and the feature sequence of the encrypted medical image is extracted by combining the perceptual hashing technique. Finally, integrating the zero watermarking technique and the idea of a third party are steps to achieve embed and extract watermark information. The experimental findings demonstrate the algorithm&s;s strong resistance to both conventional and geometric attacks, ensuring the security of the carrying medical image information, and demonstrating some potential applications.