Xiong Y, Wang Y
Appl Opt. 2022 Apr 1;61(10):2743-2749. doi: 10.1364/AO.455250.
In this paper, the security of a security-enhanced optical cryptosystem based on full phase encoding and equal modulus decomposition (EMD) is evaluated. Compared to the original EMD-based image scheme in which plaintext is the amplitude information of the spectrum to generate two complex-valued masks with equal moduli, phase-encoded plaintext is regarded as the input of EMD-based structure to generate masks in the full phase encoding and EMD combined cryptosystem. It seems that the security strength has been improved by decreasing the number of constraints in the iterative attack; however, it is found that this scheme is still under security risk. Thus, we propose two iterative attacks based on normalization operator and phase-retrieval techniques with different constraints to break the security-enhanced scheme. Numerical simulations are carried out to demonstrate the feasibility and effectiveness of the proposed attacks.
本文评估了一种基于全相位编码和等模分解（EMD）的增强安全性光学密码系统的安全性。与原始的基于EMD的图像方案相比，在原始方案中明文是频谱的幅度信息以生成具有相等模值的两个复值掩码，在全相位编码和EMD组合密码系统中，相位编码的明文被视为基于EMD结构的输入以生成掩码。通过减少迭代攻击中的约束数量，似乎安全强度得到了提高；然而，发现该方案仍处于安全风险之中。因此，我们提出了两种基于归一化算子和具有不同约束的相位恢复技术的迭代攻击，以破解增强安全性的方案。进行了数值模拟以证明所提出攻击的可行性和有效性。
