Reversible data hiding in encrypted images with multi-prediction and adaptive huffman encoding

Figure 4 illustrates the framework of the proposed method, from which we can identify three processes: pre-processing and image encryption by the content-owner, data embedding by the data-hider, and data extraction and image decryption by the receiver. Prior to image encryption, the content-owner first uses the MED+GAP predictor to compute a label map of non-reference pixels in the original image, and then encodes the generated label map using adaptive Huffman coding and embeds it in the encrypted image. After obtaining the label map, the data-hider can embed the secret data into the…