Algorithm of Image Encryption based on Permutation Information Entropy

Criterion for choosing chaos map to drive image bit permutation based on chaos permutation information entropy is proposed. An algorithm for image bit permutation is designed based on the fact that the output trajectory of chaotic system is very unpredictable. Image smallest granularity scrambling, namely, bit space maximum scrambling is implemented by applying the chaos that has been selected. Image substitution algorithm according to the principle of chaos map stretch and fold is designed to finish image encryption transformation to enhance the ability to resist attack. The algorithm’s key space and resistance to differential attack, and the digital characteristics of cipher-image have been analyzed. Theoretical analyses and computer simulations both confirmed that the proposed algorithm is better than Ye’s and Huang’s algorithms in the ability of scrambling, decorrelation and anti-differential attack, can protect digital image effectively. Keywords-chaos; permutation information entropy; sorting transformation