Reversible watermarking scheme for medical images

Reversible watermarking is quite effective in transfer of small data through the medium of images and both could be easily recovered at the receiving end. Because of this it´s widely used in medical imagery. Here we propose a technique based on difference expansion, in which the transferred image consist of the original image embedded with, the patient information, hash of the original image and the payload required for the recovery. In order to provide confidentiality, the payload and the patient information both are encrypted using symmetric key based encryption algorithm, this provides that the patient information is confidential and the image too could not recovered for diagnoses under attack. Hash of the recovered image is calculated and compared with the recovered embedded hash to make sure that the image has not been tampered.