Generalized optical encryption framework based on Shearlets for medical image

The security of medical image data for transmission and storage is a critical issue. Texture information of medical images is important for diagnosis. Since Shearlets is particularly effective in characterizing texture information, in this paper, we propose a generalized optical encryption framework based on Shearlets and double random phase encoding (DRPE) especially for medical images. In the proposed encryption framework, the secret medical image is first decomposed into n sub-images with shearlet transform. Then, the sub-images or pixel positions are shuffled by scrambling algorithm. Subsequently, the shuffled sub-images are synthesized into one image. Finally, the synthesized image is encoded with DRPE. The security level of the proposed encryption framework can be improved by changing the parameters of shearlet transform and selecting different methods for scrambling pixels and synthesizing multiple images to single image. Extensive simulation results have shown the performance of the proposed optical encryption framework. The proposed encryption framework can be improved along with novelty scrambling method and reversible synthesize methods.