A Chaotic Image Encryption Algorithm Using Pixel Permutation-diffusion and Bit Replacement

A new chaotic image encryption algorithm using pixel permutation-diffusion and bit plane operations is presented. Firstly, the system parameter and initial value of 1D skew tent system are modified by applying the characteristic quantity of plain-image to strengthen the cryptosystem resisting known/chosen plaintext attacks. The generated chaotic sequence is then utilized to scramble the plain-image. Secondly, two chaotic image sequences are generated by 2D skew tent system, and the scrambled plain-image is split and embedded into the two chaotic image sequences by bit plane replacement. The bitwise XOR operation and forward diffusion operation are then conducted on the two resulted chaotic sequences embedded plain-image information to strengthen the security of the proposed cryptosystem. Experimental results and performance analysis demonstrate that the proposed encryption algorithm can effectively withstand statistical analysis like entropy analysis, histogram analysis, adjacent pixels correlation analysis, etc. The proposed image encryption algorithm has strong key sensitivity, strong plain-image sensitivity, and large enough key space as well.