Reversible data hiding in encrypted images using adaptive classification encoding

An essential information security technology is reversible data hiding in encrypted images (RDHEI), which not only transmits secret data through the encrypted carrier image, but also restores the carrier image error-free. One common framework for RDHEI is vacating room after encryption (VRAE); nevertheless, its embedding capacity tends to be undesirable. We present an RDHEI approach with an enhanced adaptive classification embedding mechanism to ameliorate the issue. To maintain the correlation of pixels within the block, the content owner first encrypts the cover image employing block-level stream encryption and block permutation. The data hider computes the amount of identical bit planes within a block beginning with the most significant bit (MSB) utilizing the MSB prediction method to derive the higher-order bit plane-related coefficients (HOBPRCs). These coefficients are integrated as block labels within the corresponding blocks through the Huffman coding. Then, a refinement classification compression is exploited, mainly using different compression strategies according to different HOBPRCs. For blocks with small HOBPRCs, the adaptive coding strategy is recommended to improve embedding capability. The average payloads of the suggested RDHEI method for the BOSSbase and BOWS-2 datasets are 2.9652 bpp and 2.7615 bpp, respectively, and the experimental results demonstrate the effectiveness of the proposed method.