Secure and effective image storage for cloud based e-healthcare systems

For a cloud based system, storage volume, users´ privacy and computing capacity are three key issues. In this paper we propose a secure and effective cloud based image storage framework for e-healthcare systems with images transmission and storage. The main contribution of the proposed framework is a high compression ratio method for encrypted images. We first analyze the difficulties of encrypted image compression and discuss the drawbacks of current compressive sensing (CS) based encrypted image compression. Then we propose a novel lossy encrypted image compression method, which is based on the CS, dictionary coding, and recent sparse couple reconstruction theories. The experiment results show that compared to state-of-the-art encrypted image compression methods and classical JPEG/JPEG2000 compression methods, the proposed scheme can achieve much higher compression ratio of JPEG2000 with the similar reconstruction quality, meanwhile can obtain much better reconstruction quality than CS based methods with a similar compression ratio.