OT24:Optical color image encryption based on Two-dimensional quantum walks and 24-bit-plane permutation

The Double Random Phase Encoding(DRPE) image encryption scheme has received a lot of attention when processing color images because it can encrypt R, G, and B components in parallel, in the era of big data. However, the DRPE scheme has two issues to be addressed: First, the DRPE scheme for color images ignores the correlation among R, G and B components, which leads to the decline of the robustness of the encrypted images: Second, DRPE schemes based on discrete Fourier transform (DFT) and discrete fractional Fourier transform (DFRFT) are vulnerable to linear attacks and known plain-text attacks (KPA). Therefore, an optical color image encryption method based on two-dimensional quantum walking and 24-bit plane permutation is proposed in this paper. The phase modulation of DRPE utilizes random numbers generated by two-dimensional quantum walks, generalized Arnold used to confuse the imaginary and real parts of an encrypted image. 24-bit planar permutation reduces the correlation between the three layers (R, G, and B), while generalized Arnold enhances DRPE resistance to linear attacks. The effectiveness and safety of the scheme are verified by experiments.