A DWT Based Steganographic Method Using Prime First Mapping (PFM)

Steganography takes up a distinctively extraordinary space in facilitating secret communication in this technology aided world. It differs from Cryptography in such a way that the outputs attained after various steganographic operations are apparently kept hidden. The output, in cryptography, appears to be visibly encrypted. In this context, a new concept in the steganographic horizon is proposed, where the confidential information is hidden in such a fashion, that it does not captivate any bit of suspicion of the hackers. And even if it does, it is almost impossible to crack the security. To begin with, we have applied 2D Haar Discrete Wavelet Transform on the chosen cover or carrier image. We are hence able to figure out all of its coefficient matrices. This step is followed by applying our proposed Prime First Mapping (PFM) approach for embedding purpose where unique concepts based on the prime and non-prime location values of the existing pixels have been used. The results obtained clearly prove the novelty of this approach, in terms of all the evaluated benchmark techniques. The embedding capacity is eminently high and the moderate PSNR value shows the imperceptibility of the stego-image. The similarity measure also substantiates its efficiency in preserving the image quality.