Reversible Data Hiding in Encrypted Image Based on Block Classification Scrambling

To improve the security and the quality of decrypted image, this work proposes a reversible data hiding in encrypted image based on block classification scrambling. In image encryption phase, all 8 x 8 blocks are firstly classified into the smooth blocks and texture ones and the corresponding block-type matrix is generated according to their most significant bits (MSB). And then the XOR-encrypted smooth and texture blocks are scrambled by the encryption key, respectively. At last, the encrypted image is generated by scanning the scrambled smooth and texture blocks in order. The risk of content disclosure of encrypted image obtained by the proposed method is reduced since the value and location of each pixel are both protected. Experimental results demonstrate that the probability for lossless recovery of proposed method is 100% even if for texture image Baboon at a high embedding rate of 0.15 bpp.