A Proactive Approach to Reversible Data Hiding in Encrypted Images

We present a reversible data hiding method for encrypted images that guarantees reversibility, i.e., the exact recovery of secret data and cover image by the receiver. This work is based on Zhang's reversible data hiding in encrypted images. Spatial correlation of pixels in the cover image is exploited for data hiding. In the proposed method, the sender proactively chooses suitable blocks in the cover image to hide secret data. The stego image is then encrypted so that privacy of cover image as well as secret data is protected. Zhang's method attains reversibility only with sufficiently large block size, thereby sacrificing payload capacity. The proposed method achieves reversibility at all block sizes, while significantly improving the embedding capacity over many of the state-of-the-art methods. (C) 2015 The Authors. Published by Elsevier B.V.