Single-Channel Color Image Encryption Based on Iterative Fractional Fourier Transform

A single-channel color image encryption is proposed based on iterative fractional Fourier transform. The color image to be encrypted is first separated into three independent channels: red, green and blue. Then, the red and green components are encrypted into a single one based on iterative fractional Fourier transform. Similarly, the interim image and blue component are encrypted into the final gray scale ciphertext with stationary white noise distribution, which has camouflage property to some extent. In the process of encryption and decryption, three different groups of fractional orders, five private phase functions and one common phase function are used as keys to enhance the security of the proposed system. Additionally, the proposed iterative fractional Fourier transform algorithm has faster convergent speed. Simulation results verify the feasibility and effectiveness of this method.