Completely Separable Reversible Data Hiding in Encrypted Images

摘要

As an emerging technology, reversible data hiding in encrypted images will be useful and popular in cloud computing due to its ability to preserve the confidentiality. In this paper, a novel framework of completely separable reversible data hiding in encrypted images is proposed. The cover image is first partitioned into non-overlapping blocks and specific encryption is applied to obtain the encrypted image. Then, image difference in the encrypted domain can be calculated based on the homomorphic property of the cryptosystem. The data-hider, who does not know the original image content, may reversibly embed secret data into image difference using a modified version of histogram shifting technique, Data extraction is completely separable from image decryption, i.e., data extraction can be done either in the encrypted domain or in the decrypted domain, so that it can be applied to different application scenarios. In addition, real reversibility is realized, that is, data extraction and image recovery are free of any error. Experimental results demonstrate the feasibility and efficiency of the proposed scheme.