Diamond shape division reversible data hiding in encrypted images

Visible data hiding embeds secret messages in media to reduce distortion such that an unintended observer will not be aware of the existence of the hidden mes- sages. The conventional reversible data hiding (RDH) embedding capacity is so low. This study focuses on the need for higher embedding capacity, and then proposes an improving reversible data hiding method in encrypted images. Natural images contain strong corre- lations among adjacent pixels. Generally statistical analysis on large amounts of images shows that averagely adjacent 8 to 16 pixels are correlative in horizontal, vertical, and also diagonal directions. In this study, a diamond shape division contains 13 pixels in a block, meets the characteristics of natural images. The experimental results show the proposed method not only enhances the embedding capacity but also remains high security.