Reversible Data Hiding in Encrypted Images for Large Data Size Using DCT

This letter proposes a method of reversible data hiding method in encrypted images for large data size using DCT. Reversible data hiding is a technique to embed additional message into some cover media with a reversible manner so that the original cover content can be perfectly restored after extraction of the hidden message. The data extraction can be achieved by examining the block smoothness. This letter adopts a scheme for measuring the smoothness of blocks, and uses the closest match scheme to further decrease the error rate of extracted-bits. The experimental results reveal that the proposed method offers good performance for hiding large data size files in an image. It is observed from the method that an image with more details gives better peak signal to noise ratio than image with less detail.