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基于Hash函数敏感性的医学图像精确认证

钟晓燕1, 冯前进1, 陈武凡1, 江贵平1(南方医科大学生物医学工程学院,广州 510515)

摘 要
为了有效地鉴定医学图像的真实性和完整性,提出了一种基于提升格式的整数小波变换和Hash函数敏感性相结合的易碎水印方法。该方法在不需要原始图像的条件下,就可以检测到图像1bit的篡改,还可以对篡改区域进行定位。与现有基于小波变换的数字水印方法相比,可以在减少计算复杂性的同时,提高嵌入水印图像的质量。而MD5算法构造的Hash函数的运用提高了水印安全性和水印检测的能力。实验结果表明,本文算法对篡改具有极强的敏感性,且整个认证过程还需密钥完成检测,安全性很高,认证过程计算简单且准确性很高。
关键词
Hard Authentication for Medical Image Based on Sensitivity of Hash Function

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Abstract
A fragile watermark is designed using integral wavelet transform combined with hash function in order to verify the integrity of medical images. Even 1 bit of change in the picture can be sensed. Furthermore the region distorted can be easily oriented in this algorithm without an original image. Compared with the traditional digital watermark based on wavelet transform, the integer wavelets not only simplify the calculation but also improve the quality of watermarked image. And the hash function constructed with MD5 algorithm increases the security and ability of tamper localization of watermark. The results of experiment indicates that watermark scheme is highly sensitive to the distortion of the image. Since it requires a key during both the insertion and the extraction procedures, it has high security and the whole process is simple and accurate.
Keywords

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