Message Dependent Steganography Using Variable Modulo Operation Technique
Sukhiit Singh, Vibha Jain, Amanpreet Singh · 2018
In message dependent steganography, a technique called variable modulo operation is used on a preprocessed message. Before applying this operation, first we convert a message to a more meaning full representation. In this scheme the message to be embedded is first analyzed to get total number of unique ASCII characters. The actual unique random message ASCII codes are then mapped to an efficient single dimensional array. The mapping is done in such a way that the high frequency ASCII character codes are mapped to the specific locations of the newly formedo array. The array serves two purposes first it represents ASCII codes in a continuous manner with lower value and secondly mapping produces lesser distortion in the final stego image based on the central limit theorem. Further the new character codes are operated upon by a variable modulo number whose value depends upon the number of unique characters used in the message. An RGB image file is taken as cover. Peak Signal-to-Noise (PSNR) and Structural Similarity Index (SSIM) values are calculated under the proposed algorithm that produces more secure stego-image with lesser distortion as compared to other techniques.