Efficient reversible data hiding in encrypted images

• A novel scheme of reversible data hiding for encrypted images is proposed.
• Additional data and compressed encrypted data are embedded with an efficient way.
• Original image can be perfectly recovered with the aid of side information.
• The better rate-distortion performance in directly decrypted version is obtained.

This paper proposes a novel scheme of reversible data hiding in encrypted images based on lossless compression of encrypted data. In encryption phase, a stream cipher is used to mask the original content. Then, a data hider compresses a part of encrypted data in the cipher-text image using LDPC code, and inserts the compressed data as well as the additional data into the part of encrypted data itself using efficient embedding method. Since the majority of encrypted data are kept unchanged, the quality of directly decrypted image is satisfactory. A receiver with the data-hiding key can successfully extract the additional data and the compressed data. By exploiting the compressed data and the side information provided by the unchanged data, the receiver can further recover the original plaintext image without any error. Experimental result shows that the proposed scheme significantly outperforms the previous approaches.