Asymmetric color image encryption scheme using discrete-time map and hash value

A chaos-based asymmetric color image encryption scheme is designed. The hash value of the plain image is transformed into three initial values for the piecewise linear chaotic map (PWLCM), which is iterated to generate three pseudo-random sequences to diffuse the red, green and blue components respectively. In the encryption process, the hash value and the initial iteration number m are served as keys, and in the decryption process, three initial values for PWLCM and the initial iteration number n are served as keys. Numerical results demonstrate the feasibility and effectiveness of the proposed asymmetric cryptosystem for color image encryption.