Reversible Data Hiding in Encryption Domain based on two dimensional histogram shifting and secure encryption system

Reversible Data Hiding in Encryption Domain (RDHED) can be used in different areas such as secure remote sensing or telemedicine. Since data structure is completely changed after a reliable encryption process, custom reversible data hiding methods are not efficient to perform RDHED. In this paper, a reversible method is proposed to embed extra information in the encryption domain by designing two dimensional (2-D) error histogram. According to the proposed method, target pixels are predicted in the encryption domain to design a 2-D error histogram. The obtained histogram is shifted according to a novel pattern for data insertion. 2-D histogram shifting makes it possible to shift bins of the error histogram in various directions. This property augments embedding capacity and improves quality of directly decrypted images. To perform a secure encryption process, an improved Closed-Loop Chaotic Encryption System (CLCES) has been designed. The proposed CLCES performs a sensitive encryption process in a closed-loop system. Extensive experiments have been conducted to evaluate the performance and security of the proposed method. Obtained embedding capacity has been 0.128 bit per pixel by taking average values over 1000 test images and using least square predictor. Results confirm superiority of the proposed method in comparison with other schemes.