Encryption and data insertion technique using region division and histogram manipulation

A separable encryption and data insertion method is proposed in this paper. The input image is divided into 2 parts, where the first part is manipulated to mask the perceptual semantics, while the second part is processed to hide data. The binary image, which is the data to be inserted, further divides the second part of the input image into 2 regions called the 'zero' and 'one' regions. Pixels of the original image at position coinciding with the 'zero' region are darken, while those coinciding with the 'one' region are brightened. The darkening and brightening processes are performed by using histogram matching technique. The proposed joint method is separable, where the inserted binary image can be extracted directly from the masked image or from the reconstructed image. The proposed method is also commutative because the same results is achieved irregardless of the order of processing in encrypting and inserting data. Experiments were carried out to verify the basic performances of the proposed method.