为了更好地利用混沌进行图像保密，基于排序变换设计了一个混沌图像置乱算法，新算法小经过量化．而是直接通过混沌序列的排序变换来得到图像置换的地址码，这就有效地避免了量化必须已知混沌轨道分布密度函数的要求，同时也降低了算法的时间复杂度。由于排序变换的强不规则性，因此使新的混沌图像置乱算法具有较强的安全保密性能。通过对新算法的置乱性能进行的实验分析结果表明，新算法不仅具有良好的置乱性能．而且可以有效地保障加密图像的安全。

This paper proposes an algorithm of chaotic images scrambling based on the sort transformation. The new algorithm obtains the address codes of the images transposition by the sort transformation of the chaotic sequence and does not need the quantification. The probability density function of the chaotic orbits must be known by the method of quantification. The new algorithm, however, overcomes this disadvantage, which not only facilitates the choice of chaotic systems but also reduces the time complexity of traversing the images scrambling quantified by chaos. As a result, it increases the speed of scrambling images. Due to the strong irregularity of sort transformation, the new chaotic images scrambling algorithm possesses high-level security. The paper also analyzes the scrambling performance of the new algorithm in a statistical way. The results of the analysis indicate that the algorithm bears nice scrambling capability and guarantees the security of the encrypted images effectively.