Preview-supported Copyright Image Sharing

In view of the fact that digital watermarking technology does not consider the preview needs of users in copyright image sharing scenarios, as well as the limitations of software control method and additional information method, a copyright image sharing scheme that supports previewing part of the visual content of the original image directly from the encrypted image is proposed. To this end, the idea of thumbnail preserving encryption is introduced into the user-side embedded watermarking scheme, and a blurred version of the original image content is presented on the encrypted image through pixel adjustment. The pixel bits to be adjusted are embedded into the hidden area by means of information hiding in advance to ensure the correctness of decryption. Moreover, the user watermark is embedded into the image at the same time of decryption, which is used to track the unauthorized redistribution behavior. In this way, not only the preview needs of the user during the sharing process is met, but also the copyright of the image is protected. The results of theoretical analysis and experimental tests demonstrate the security, feasibility, efficiency, and robustness of the proposed scheme.