Abstract-Nowadays, many applications have been appeared due to the rapid development in the term of telecommunication. One of these applications is the telemedicine where the patients' digital data can transfer between the doctors for farther diagnosis. Therefore, the protection of the exchanged medical data is essential especially when transferring these data in an insecure medium such as the cloud computing environment, where the security is considered a major issue. In this paper, two security approaches were presented to guarantee a secure sharing of medical images over the cloud computing environment by providing the mean of trust management between the authorized parities of these data and also allows the privacy sharing of the Electronic Patients' Records string data between those parities while preserving the shared medical image from the distortion. The first approach apply spatial watermarking technique while the second approach implements a hybrid spatial and transform techniques in order to achieve the needed goal. The experimental results show the efficiency of the proposed approaches and the robustness against various types of attacks.

Abstract-Recently, sharing patients' history all over the world becomes a necessity to facilitate the storing, transforming and consequently the further diagnosing processes. As for medical images, there are special requirements needed such as the quality that should kept high while preserving the security and privacy arrangements especially when dealing with a public sharing environments such as the cloud computing. Therefore, performing limited sharing through the trust management will help to achieve the security needs. This paper introduce an efficient watermarking technique to guarantee the secure DICOM images sharing over the cloud computing environment using two levels of authentication through private secret key, dynamic embedding/extraction and Cloud watermarking algorithms. The experimental results are promising and showing that the proposed technique gives high PSNR for the watermarked images and their ROI respectively. It also shows robustness against the transition attacking attempts and preserves the DICOM format of the medical images.Index Terms-Cloud computing, ROI, cloud drops, dynamic embedding, spatial synchronization, watermarking. I. INTRODUCTIONAs a result of the rapid development in the field of technology, a lot of applications began to appear in different disciplines such as teleshopping, bioinformatics, e-banking, telemedicine … etc. Telemedicine, this field that considered as critical one since it includes sending and receiving of the medical images through the healthcare professionals over the telecommunication which in turn facilitate the work of the professionals by overcoming the distance barriers [1]. However, since these critical data are transmitted over the computer networks, this makes it more likely to be attacked especially when the used network is the cloud computing which is a new technology trend that offers resources encapsulation on the Internet in the form of dynamical, scalable, and virtualized services. By exploiting these services, users outsource their data to the cloud so as to enjoy the reduced upfront maintenance and capital costs. However, adopting a cloud computing paradigm may have positive as well as negative effects on the data security of service consumers [2]. A data owner loses control over the data outsourced to a machine that can be physically located anywhere in the world. This machine is operated by a cloud service provider which is located at an unknown location to Manuscript received March 1, 2013; revised April 29, 2013. Fatma E.-Z. A. Elgamal and Noha A. Hikal are with the Information Technology Department, Faculty of Computers and Information System, Mansoura University, Mansoura, Egypt (e-mail: fatma.zahraa@hotmail.com; nmhikal@yahoo.com).F. E. Z. Abou-Chadi is with the Communication Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt (e-mail: fabochadi@ieee.org). a data owner [3]. The loss of control over data is further enlarged with the lack of managing users' access to the data from practical cloud computing perspective...

The fast development in the term of telecommunication helps on the appearance of variety of modern applications such as the telemedicine where the patients' digital data can transfer over insecure mediums between the doctors for farther diagnosis and dealing with these transmitted data. Therefore, the protection of the exchanged medical data is essential especially when working on the cloud computing environment, where the security is considered a major issue. In addition to the security, the high visibility of the medical images must also be achieved. This paper presents a novel approach that guarantees the secure sharing of medical images over the cloud computing environment by providing the mean of trust management between the authorized parities of these data and also allows the privacy sharing of the Electronic Patients' Records (EPR) string data between those parities while preserving the shared medical image from the distortion. The experimental results show the efficiency of the proposed scheme and also the robustness against various types of attacks.