Role-Based Access Control for Secure Retrieval of Triple-Watermarked DICOM Medical Images

The rapid adoption of digital medical imaging has increased the need for secure storage, transmission, retrieval, and controlled access to medical images. Digital Imaging and Communications in Medicine (DICOM) is widely used for storing and exchanging medical images together with associated patient and clinical information. However, unauthorized access, modification, duplication, and disclosure of sensitive medical information remain important security concerns. This paper proposes a role-based access control framework for the secure retrieval of triple-watermarked DICOM medical images. The proposed framework combines Discrete Wavelet Transform (DWT) and Singular Value Decomposition (SVD) with Role-Based Access Control (RBAC). Three independent watermarks are embedded into selected DWT-SVD coefficients to provide authentication, integrity verification, and ownership protection. RBAC is then applied to control which watermark or associated information can be retrieved by different categories of authorized users. Doctors, radiologists, technicians, researchers, and administrators are assigned different permissions according to their operational requirements. The framework separates authentication from authorization and limits sensitive information exposure according to user roles. Performance can be evaluated using Peak Signal-to-Noise Ratio (PSNR), Structural Similarity Index (SSIM), Normalized Correlation (NC), Bit Error Rate (BER), extraction accuracy, and execution time. The proposed approach provides a combined mechanism for image protection and controlled information retrieval while maintaining the visual quality of DICOM images.