Steganography of Quantum Color Images Based on Blocking and Gray Level Difference.

Steganography of quantum images is restricted by high fidelity and robustness, which limit hiding capacity and decrease visual quality. To improve the concealment of steganographic embedding of secret messages and enhance embedding capacity, the present study proposed a quantum red-green-blue (RGB) image steganography based on image block and gray level difference. First, digital color images were represented by quantum models and divided into non-overlapping blocks. Second, reference pixels in the blocks were selected, and gray level difference between the reference pixels and the G channel of other pixels was calculated. Third, according to the location of the difference, different bit planes where secret messages were embedded into the R and the B channels of the carrier image were determined. Finally, steganographic image was divided into blocks. The G channel gray difference was calculated, and the original secret message was extracted. Results demonstrate that quantum RGB image steganography has a steganographic capacity of four bits per pixel, and its quantum circuit is less complex. In comparison with other quantum image steganographic methods, the proposed method ensures a large steganographic capacity while realizing satisfactory visual quality and steganographic concealment. The study provides reference significance for exploring data hiding and quantum image security based on quantum RGB image block. [ABSTRACT FROM AUTHOR]