Abstract: A digital watermarking algorithm is proposed based on chaotic scrambling and discrete fractional_order Fourier transform. In this algorithm，watermarks are embedded in the fractional Fourier domain，and it is extracted by correlation detection method. Pseudo-random，sensitive to initial value of chaotic sequences，and the fractional Fourier transform improve the security of the digital watermark. By simulations and tests of anti-attack performance，the invisibility of the watermark is very good，and this algorithm is robust to JPEG compression，filtering，noise and other attacks.

Key words: digital watermark, fractional_order Fourier transform, chaotic scrambling

摘要： 基于混沌置乱以及离散分数阶Fourier变换，提出一种数字水印算法，该算法在分数阶傅里叶域嵌入水印，并用相关性检测的方法来提取水印。混沌序列的伪随机性和初值敏感性以及分数阶Fourier变换的变换阶数为数字水印的安全性提供了保证，通过对算法的仿真以及抗攻击性能测试，该数字水印有较好的不可感知性，算法对JPEG压缩、滤波、噪声等攻击具有良好的鲁棒性。

关键词: 数字水印, 分数阶Fourier变换, 混沌置乱