Double secret key based medical image watermarking for secure telemedicine in cloud environment

This paper presents a highly secured new image watermarking scheme using two secret keys to prevent unauthorized access of information stored in cloud environment. The proposed scheme is applied for secure medical information transmission or its cloud storage. The scheme is implemented in two steps. In first step, randomization of patient information is done based on a password secret key before embedding it into the cover medical image. Second step is to hide the watermarked image into a secret key image before cloud storage so that even if the stored image is hacked or leaked, the cover medical image along with embedded patient information cannot be retrieved by the hacker. In this paper we have proposed a novel watermarking algorithm for medical images by randomizing the information according to the secret password key and then embedding it into the cover medical image followed by embedding of cover image into another secret key image. The proposed scheme aims to protect sensitive information transfer and cloud storage from unauthorized access. Extraction of the embedded information at the receiver end is done in two steps. Firstly, non-blind detection is carried out in which cover medical image is extracted with help of secret key image. In the second step, binary image watermark is extracted by analyzing the DCT (Discrete Cosine Transform) coefficient values. Performance of the proposed algorithm is analyzed by varying the quality factor of JPEG compression and sub-band decomposition levels.