An adaptive pixel mapping based approach for reversible data hiding in encrypted images

Reversible data hiding (RDH) is a widely studied research domain due to the extensive applications in medical image transmission, military image transmission, and cloud computing. In this paper, we propose a novel RDH scheme in encrypted images which is having a high embedding rate without affecting the bit error rate. To perform data hiding, all the non-overlapping pixel sub-arrays from the encrypted image will be considered in a predefined order, and one-bit from the secret message can be hidden in each of the pixel sub-arrays through a controlled pixel mapping technique. The pixels in a selected sub-array.. will be split into two groups: odd pixels and even pixels according to the parity of the index of the pixels. All the even pixels will be replaced by a new pixel value based on a predefined mapping function to hide a secret bit 1. To embed bit-value 0, no need to do any modifications in the pixel sub-array P. A new correlation measure between adjacent pixels is introduced in this manuscript to extract the secret message bit and to restore the original image. All the simulations of the proposed scheme are done on the standard images from USC-SIPI image dataset. The results show that the proposed scheme achieved a very good embedding rate without affecting the bit error rate or image recoverability.