为了实现图像认证,提出了基于混沌理论的图像hash算法。首先将原始图像经过置乱得到加密图像,然后对差值矩阵进行调制、量化,得到固定长度的图像hash序列。算法讨论了图像的缩放和JPEG压缩对图像hash序列的影响,当阈值为0.1时,对上述的攻击方法进行了实验,结果表明,图像对这两种攻击具有一定的鲁棒性。
To meet the needs of the Image Authentication,proposed image hash algorithm based on chaos theory.To begin with,encrypted the original image by Logistic map.After that,difference matrix was modulated and quantified,and then obtained the fixed length of hash sequence.It discussed that the image scaling and JPEG compression were influence on the robustness of the hash sequence.It pointed that robust of the proposed scheme against the above attacks when the threshold t is 0.1.The experimental results indicate that the algorithm has the robust to against the above attacks,then the method is an effective for studying image authentication.