부산대학교 도서관

The proliferation of portable camera devices, represented by smartphones, is increasing the risk of sensitive internal data being leaked by screen shooting. To trace the leak source, a lot of research has been done on screen-shooting resilient watermarking technique, which is capable of extracting the previously embedded watermark from the screen-shot image. However, all existing screen-shooting resilient watermarking schemes follow the owner-side embedding mode. In this mode, the management center will suffer heavy computational and communication burden in the case of numerous screens, which hinders the system scalability. As another embedding mode of digital watermarking, client-side embedding can solve the above scalability problem by migrating the watermark embedding operation to the same time when the screen decrypts the image. By designing a pair of image encryption and personalized decryption algorithms based on matrix operation, this paper is the first to realize the client-side embedding of screen-shooting resilient watermarking. In this implementation, challenges are overcome and the following key achievements are attained. First, our scheme embeds watermark using the algorithm of Fang et al. without modification, and thus fully inherits its robustness against screen shooting. Second, the original image is securely encrypted and the watermarked image can be directly retrieved through decryption. Third, the secrecy of the screen watermark is ensured by concealing the embedding pattern. Finally, our scheme is validated by experiments, which shows that the efficiency advantage of client-side embedding is realized while maintaining robustness.