Enhancing Reversible Data Hiding Technique in Encrypted Images

Since several years, the protection of multimedia data is becoming very important. The protection of this multi- media data can be done with encryption or data hiding algorithms. Recently, more and more attention is paid to reversible data hiding (RDH) in encrypted images, since it maintains the excellent property that the original cover can be losslessly recovered after embedded data is extracted while protecting the image content’s confidentiality. In this paper, we propose a novel method by reserving memory space before encryption with a traditional RDH technique, and thus it is easy for the data hider to reversibly embed data in the image. The proposed method can achieve real reversibility, that is, data extraction and image recovery are free of any error. A new idea is to apply reversible data hiding algorithms on encrypted images by wishing to remove the embedded data before the image decryption. Recent reversible data hiding methods have been proposed with high capacity, but these methods are not applicable on encrypted images. The image like differential expansion, histogram shift or the combination of both the techniques. This is useful in the way that this method recovers the image with its original quality with improved PSNR ratio.