基于双密钥分割合成滤波的相位编码的密钥恢复算法

A key retrieval algorithm for the phase-coding based on segmented composite filtering

提出了一种分割合成滤波(SCF)相位编码的新密钥恢复算法。恢复过程中,首先利用已知明文攻击的方法获取SCF相位编码系统的分割模板;然后根据模板的信息,借助蒙特-卡罗法模拟分析出各个像素点的归属情况。进而利用分割模板的生成规则恢复出密钥频谱的强度信息,在此过程中提出了强度池(IP)的概念,以解决强度修正的问题。最后借鉴相位恢复的思想,经多次迭代恢复出密钥频谱的相位信息,进而恢复出所需密钥。结果显示,运用恢复出的密钥可成功地对使用该编码的图像进行译码,并且得到的译码图像质量很好。

A novel key retrieval algorithm for phase-coding based on double-key segmented composite filtering（SCF） is proposed.During the recovering,at first the segmented phase mask（SPM） of SCF coding system was obtained by the known-plaintext attack.Then,according to the content of the mask,the affiliations of the phase mask were analyzed by Monte Carlo method.On that basis,the intensity distribution of the key,which needs to be retrieved,could be confirmed depending on the regulation of SPM generation.During this process,the concept of intensity pool（IP） was proposed to solve the problem of intensity-amendment.At last,the phase of the key was retrieved by the idea of phase retrieval,and then the retrieved key could be obtained after several iterations.After the experiment,it can be concluded that the retrieved key can decrypt the cipher text successfully.And the quality of decrypted image is very good.