Flexible Data Hiding and Extraction in EtC Images

This paper proposes a data hiding method for compressible encrypted images called the encryption-then-compression (EtC) images. We allocate bit planes of an original image to an encryption field and a data hiding field, where the upper 7 bits are encrypted by a compressible encryption (CE) method and LSBs are replaced with payload bits. By conducting the encryption and data hiding processes in the independent fields, the proposed method can embed and extract the payload flexibly without any complex condition and preprocessing. Experimental results and discussion show the effectiveness of the proposed method in terms of lossless compression efficiency by using JPEG-LS and JPEG 2000, marked-image quality, and robustness against attacks.