Chapter 11 - Secure and reversible data hiding scheme for healthcare system using magic rectangle and a new interpolation technique

Abstract

In this chapter a very high capacity and secure medical image information embedding scheme capable of hiding an Electronic Patient Record (EPR) imperceptibly in grayscale medical images for healthcare applications has been proposed. To ensure the reversibility of medical images, a new image interpolation technique has been used to scale up the original image to obtain the cover image. The cover image pixels have been divided into two types: Seed pixels and nonseed pixels. The Electronic Patient Record (EPR) has been embedded only in nonseed pixels while no embedding has been carried out in seed pixels, to facilitate reversibility. A fragile watermark has been embedded in addition to the EPR, to make the proposed scheme capable of detecting any tampering of EPR during its transit from transmitter to receiver. The fragile watermark is also used for content authentication at the receiver. At the receiving end, first we extract the fragile watermark; if it is the same as the one embedded, signaling that the EPR has not been attacked during transit, the EPR is extracted. Otherwise, the system uses a retransmission request instead of wasting time to extract the compromised Electronic Patient Record (EPR). For ensuring the security of the EPR, we encrypt it using a magic rectangle. Embedding has been carried out using least significant bit (LSB) substitution. The scheme has been evaluated for perceptual imperceptibility and content authentication by subjecting it to various image processing and geometric attacks. Experimental results reveal that the proposed system, besides being completely reversible, is capable of providing high-quality stego-images (term used to refer to the image containing the embedded data) for fairly high payload. Further, it has been observed that the proposed technique is able to detect tampering. A comparison of the observed results with those of some state-of-the-art schemes show that our scheme performs better.