Asymmetric color image encryption scheme using 2D discrete-time map

A chaos-based asymmetric color image encryption scheme is designed, and the advantage is to distribute different keys to different receiver through keys changing mechanism. The hash value of the plain image is applied to produce two initial values of the Hénon map, to generate two pseudo-random sequences. In the encryption scheme, firstly generate six pseudo-random arrays to circularly shift the red, green and blue components by rows and columns respectively, and then diffuse three color components by exclusive or operation (XOR). In the decryption process, two initial values of Hénon map, the iteration number m−n+1, the iteration times and the control parameters of Hénon map are served as keys. Numerical results demonstrate the feasibility and effectiveness of the asymmetric cryptosystem for color image encryption.