关键词: 图像加密, 混沌, Logistic映射, Cat映射

Abstract: In order to improve the security and efficiency of image encryption algorithm，a dual chaotic system combining piecewise Logistic chaotic map and Cat map is proposed.Firstly，choose a chaotic map from piecewise Logistic chaotic map and Cat map after doing an improved Logistic map，and then confirm the chaotic key.Last，the security analysis is performed at the dual chaotic maps.The experimental result shows that the algorithm has numerous key space，higher sensitivity to initial value and stranger resistant attack ability.It is a novel efficient image encryption algorithm.

Key words: image encryption, chaos, Logistic map, Cat map