Determination of optimal parameters for detecting the existence of secret information hidden by the double random-phase encoding technique

A new method based on statistical hypothesis detection for information hidden using the double random-phase encoding technique is introduced. According to this method, a series of windows are opened on the lowest bit-plane of image, and an exclusive OR (XOR) operation is performed between different pixels in every window. The results of XOR operation are then analyzed. Using this method, we can judge whether an image contains secret information encrypted by the double random-phase encoding technique. The result of the judgment may be influenced by two parameters, namely the size of the window and the threshold value. A further study is also made to determine the optimal parameters.