Lossless Optical Color Image Encryption Algorithm Based on Fast Response Decomposition and Color Space Transformation

A lossless optical color image encryption algorithm based on fast response decomposition and color space transformation is proposed. The color image is converted from RGB space to color space, and h, s and I components are extracted; h, s, I components are encoded and modulated according to random phase mask; h, s, I components are encoded and modulated based on gyrator transformation The phase and amplitude information of gyrator spectrum is obtained by introducing phase amplitude truncation mechanism, and the amplitude part is taken as ciphertext. In order to achieve lossless decryption, fast response decomposition technology is used to segment the output ciphertext, and the corresponding Q and R components are obtained. The two components are processed independently by gyrator transformation to form coding information; the output phase information is used to generate h, s, I. The decryption key corresponding to the component can obtain his image through joint encoding information and decryption key, and then convert it into RGB space to achieve lossless decryption.