CRYPTANALYSIS ON SECURE FRACTAL IMAGE CODING BASED ON FRACTAL PARAMETER ENCRYPTION
CRYPTANALYSIS ON SECURE FRACTAL IMAGE CODING BASED ON FRACTAL PARAMETER ENCRYPTION
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DOI：
10.1142/s0218348x12500041
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发表时间：
2012-03-01
影响因子：
4.7
通讯作者：
Wong, Kwok-Wo
中科院分区：
文献类型：
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作者：
Yuen, Ching-Hung;Wong, Kwok-Wo
指出了Lian等(1)提出的用于分形图像编码的选择性加密方案的脆弱性。通过比较用不同密钥加密的同一明文图像的多个密文图像，确定未加密参数在每个编码块中的位置。这使得攻击者能够通过观察每个匹配域块的长度来恢复四叉树的加密深度。有了这些深度信息和未加密的参数，攻击者就能够重建智能图像。实验结果表明，将加密的对比度比例因子和亮度偏移量替换为特定值，可以成功地对部分标准测试图像进行解码和识别。为了提高方案的安全性，提出了一些补救措施。
The vulnerabilities of the selective encryption scheme for fractal image coding proposed by Lian et al.(1) are identified. By comparing multiple cipher-images of the same plain-image encrypted with different keys, the positions of unencrypted parameters in each encoded block are located. This allows the adversary to recover the encrypted depth of the quadtree by observing the length of each matched domain block. With this depth information and the unencrypted parameters, the adversary is able to reconstruct an intelligent image. Experimental results show that some standard test images can be successfully decoded and recognized by replacing the encrypted contrast scaling factor and brightness offset with specific values. Some remedial approaches are suggested to enhance the security of the scheme.