Medical Image Watermarking for Fragility and Robustness: A Chaos, Error Correcting Codes and Redundant Residue Number System Based Approach

In this paper, a spatial domain, secure, hybrid watermarking technique for making the watermark (authentication information) robust and the host medical image highly fragile (content integrity) using BCH codes, Chaos theory and Redundant Residue Number System (RRNS), is proposed. The technique is fragile and unrecoverable in terms of the host image; however, it is robust and recoverable in terms of the watermark. This is mainly because tampering in the medical image is an unwanted thing that may result in misdiagnosis hence must be detectable while the watermark that may contains patient information, organization logo etc. must be protected against certain attacks. The host image is separated into two parts namely the region of interest (ROI) and region of noninterest (RONI) using rectangular region. The RONI part is used to embed the watermark information. Moreover, two watermarks are used; one to achieve authenticity of image and the other to achieve the robustness against both incidental and malicious attacks. Effectiveness in terms of security, imperceptibility, robustness and fragility of the proposed scheme is demonstrated by the simulations and comparison with the other state of the art techniques.