Separable and Error-Free Reversible Data Hiding in Encrypted Image Based on Two-Layer Pixel Errors

Reversible data hiding is an important topic of data hiding. This paper proposes a novel separable and error-free reversible data hiding in an encrypted image based on two-layer pixel errors. Specifically, the proposed scheme divides the original image into a series of non-overlapped blocks and permutes these blocks. Then, a closed Hilbert curve is used for scanning each block to obtain a one-dimensional pixel sequence. The pixels of the sequence are encrypted with key transmission. During data hiding, each non-overlapped block of the encrypted image is scanned in the closed Hilbert order to generate a one-dimensional encrypted pixel sequence. Finally, it exploits the histogram of two-layer adjacent encrypted pixel errors to embed secret data by histogram shifting and generate a marked encrypted image. Many experiments are carried out, and the results demonstrate that the proposed scheme reaches a high payload and outperforms some reversible data hiding schemes in the encrypted image.