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    基于秘密共享的感知鲁棒图像Hash算法

    Perceptual Robust Image Hashing Scheme Based on Secret Sharing

    • 摘要: 数字图像在经过保持图像主要内容不变的操作后虽数字表示会发生变化,但其视觉感知效果不变,对应的图像Hash值也应不变,传统密码学中的Hash函数因其对数据每个比特变化的敏感性而不适合直接应用于图像Hash的计算.针对这一问题,提出一种有效的感知鲁棒图像Hash算法,并可应用于图像检索和图像认证等领域.首先通过图像缩放和基于整体变分的非线性滤波等操作对输入图像进行正则化预处理;接着在DCT域提取图像分块与其邻域的低频系数符号关系特征矩阵,该特征可反映图像局部视觉内容的分布特性;最后利用秘密共享机制对提取出的特征矩阵进行压缩得到依赖于密钥的二进制序列,置乱后即作为最终的图像Hash值.实验结果表明,该算法对常见保持图像内容不变的操作,如JPEG压缩、高斯低通滤波及图像缩放等具有较好的感知鲁棒性,同时对于视觉显著不同的图像具有极低的冲突概率.

       

      Abstract: Since the cryptographic Hash function is sensitive, any slight change of the input message will influence the result of the Hash value significantly. But for the scenario of image hashing, the traditional cryptographic Hash functions will not be suitable. This is due to the fact that the images usually must undergo various manipulations and many of the manipulations are content-preserving, even though the digital representations of the images will be changed. This paper proposes a perceptual robust image hashing scheme, which can be applied in the fields such as image retrieval and authentication. Image resizing and total-variation-based filtering are firstly used to pre-process the input image for regularization. The sign relationship matrix of DCT low frequency coefficients for each image block and and corresponding neighborhood are then extracted, which can effectively reflect the distribution feature of local image content. The extracted feature matrix is finally compressed using the secret sharing mechanism to produce the final binary Hash after scrambling. The security of the scheme completely depends on the secret keys. Experiments are conducted to show the presented scheme has satisfactory robustness performance against perceptually content-preserving manipulations, e.g., JPEG compression, Gaussian low-pass filtering, and resizing, and simultaneously has very low anti-collision probability for the hashes of distinct images.

       

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