PVO-based reversible data hiding for encrypted images

This paper proposes a simple yet effective reversible data hiding (RDH) method for encrypted images. It guarantees exact data extraction and original image recovery from the marked encrypted image. Moreover, it is separable in the sense that the data extraction and the original image recovery can be independently processed. Specifically, we first encrypt the cover image by permutation in both block- and pixel-wise manners using a chaotic mapping. Then, we apply the pixel-value-ordering (PVO) embedding on each permuted block, to reversibly embed data into the encrypted image. Since the pixel value order is unchanged in each block after PVO embedding, the embedded data can be exactly extracted using the inverse PVO whether the marked image is decrypted or not. Experimental results show that the proposed method can provide a better decrypted marked image fidelity compared with some state-of-the-art works.