Novel high-capacity robust and imperceptible image steganography scheme using multi-flipped permutations and frequency entropy matching method

In this paper, we present a robust and imperceptible image steganography (IS) scheme for covert communication. A substantial literature presented on IS is distortion based that radically affects image imperceptibility. These schemes conceal secret information in LSBs or MSBs of cover image by using simple or random substitution. The usage of LSBs and MSBs makes these schemes vulnerable to malicious attacks like Chi-square attack and sample pair attack, and specifically, the MSBs affect the imperceptibility of cover image. Additionally, these schemes endure low capacity as large numbers of cover image pixels are required for hiding even low volume of information. The proposed IS scheme is distortion free as the negligible PVD of cover and secret image is utilized for information hiding. In contrast to LSB- or MSB-based information hiding schemes, we proposed FEM method that compares the entropy of frequencies of secret and cover image for information hiding. In fact, the elevated rate of FEM leads to high imperceptibility and capacity. Moreover, the proposed scheme uses multilayer approach that has layered transformations to frequency domain for improved robustness. Experimental investigation demonstrates that the proposed scheme has better PSNR and BPP with enhanced robustness and imperceptibility in contrast to existing schemes.