Reversible Data Hiding Method Based on Exclusive-Or with Two Host Images

In this paper we propose a reversible high capacity data hiding method applying on binary images. Since a binary image has only two colours, black or white. It is a trade-off between capacities and imperceptions in data hiding. We shuffle the secret data by a pseudo-random number generator before hiding to keep more secure. We divide the host image into nonoverlapping four by four sub-blocks, which the secret data will be concealed. Then we partition each four by four sub-block into four overlapping three by three sub-blocks. We skip the all blacks or all whites in four by four sub-blocks. We consider all four three by three sub-block to check the XOR between upper left and center, upper right and center, bottom left and center or bottom right and center, then embed one bit in each three by three sub-block. The extraction way is simply to test the XOR between the four corner pixels and the centers of each three by three sub-block. All embedding bits are collected and shuffled back to the original order. We use the same other host image to keep the record during embedding steps to reach the reversible. The experimental results show that the method provides the large embedding capacity and keeps imperceptible and reveal the host image lossless.