A New Reversible and high capacity data hiding technique for E-healthcare applications

A high capacity and reversible data hiding technique capable of tamper detection and localisation of medical images has been proposed in this paper. Image interpolation has been used to scale up the original image to obtain the cover image. The cover image is divided into n×n non-overlapping blocks. In every block pixels are classified into two types: Seed pixels and non-seed pixels. The Electronic Patient Record (EPR) is embedded only in non-seed pixels while as no embedding is carried out in seed pixels to facilitate reversibility. A fragile watermark coupled with Block Checksum has been embedded in addition to EPR for detecting any tamper to the patient data during its transit from transmitter to receiver. Embedding has been carried out using Intermediate Significant Bit Substitution (ISBS) to prevent the scheme from LSB removal/replacement attack. 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 is capable of providing high quality watermarked images for fairly high payload while maintaining reversibility. Further it has been observed that the proposed technique is able to detect tamper for all the image processing and geometric attacks carried out on it. A comparison of the observed results with that of some state-of-art schemes show that our scheme performs better and as such is an ideal candidate for content authentication of EPR in a typical e-healthcare system.