Detection of steganography in quantum grayscale images

Quantum steganography is a tool using which the very act of communication can be concealed. To prevent steganography from being misused, the scheme of detection of least significant bit steganography in quantum images based on novel enhanced quantum representation of digital images is proposed. In this scheme, the quantum image is partitioning in pixel blocks at first. Then, according to how the value of the discrimination function f changes under the flipping function F, the pixel block can be divided into three types of groups that are regular group, singular group and unusable group, respectively. The number of regular and singular groups is used to determine whether the image is embedded with secret message and calculate the length (in percent of pixels) of secret message. A series of reversible logic circuits are designed to implement the scheme with the circuit complexity of $$ {\rm O}\left( {q^{2} } \right) $$, where q is the number of qubits to represent gray scale. Finally, simulation-based experiments demonstrate the feasibility of the detection of secret message in quantum gray images.