基于叠层成像的三维信息加密系统与级联光学攻击模型的研究

This project will focus on the several scientific problems in the field of optical information security by using the physical understanding and the concerned techniques of ptychographic imaging. Discovering the inherent connection between the problem of ptychographic imaging and the problems of optical security, the project will take advantages of ptychographic imaging such as the simple configuration, the high flexibility, the excellent scalability and the robust stability, and it mainly contains: (1) The three-dimensional information cryptosystem based on ptychographic imaging: to achieve the good balance between the system security, decrypted quality and the valid security, to combine the functions of collection and encryption of three-dimensional information and to develop the concerned theory, techniques and the realizations, and to explore the application system for obtaining and securing a sort of three-dimensional biometric information. (2) The unified model of attack on cascaded optical cryptography: to construct the basic model and corresponding algorithm for attacking on classical cascaded optical cryptosystems, to attack the enhanced cascaded optical cryptosystems such as the nonlinear and the asymmetric systems, to reveal the security vulnerability and its generality, and further, to achieve the unified model, analytic paradigm and security standards for attacking on cascaded optical cryptography. Thus, our project would like to do some research work with certain characteristics and application prospects in the fields of optical information security with the unique advantages of ptychographic imaging.

本项目将借助叠层成像的物理思想与技术方法研究光学信息安全领域的相关科学问题。在发现叠层成像问题与光学加密攻击问题存在内在密切联系的基础上，本项目将充分挖掘叠层成像的构型简洁、灵活性高、扩展性好、稳定性强等突出优势，集中研究：（1）基于叠层成像的三维信息加密系统：寻求系统安全性、三维信息解密质量及有效保密容量之间的良好平衡，发展融合三维信息的获取与加密等功能为一体的理论、技术与实现，探索针对某种三维生物特征信息的采集与保密应用性系统；（2）基于叠层成像的级联光学攻击统一模型：建立适用于经典级联加密系统的基本攻击模型及其算法，攻击非线性、非对称等升级型多密钥级联加密系统，揭示其安全漏洞并建立普遍模型，进而形成级联光学攻击的统一模型、分析范式与安全标准。由此，本项目将力图发挥叠层成像的独特优势，在光学信息安全领域做出具有一定特色与应用前景的研究工作。

本项目研究了基于叠层成像原理的光学加密与隐藏系统。提出了基于单次曝光叠层成像的光学编码方法并用于水印。较详细地研究了其作为一种全光编码方法的基本特点以及其在水印应用中的具体优势。同时，提出了三维叠层编码并应用到三维信息隐藏中。从原理层次实现了不同于基于全息方法的三维信息隐藏技术，同时对该编码方式所带来的安全性与鲁棒性做了深入研究。研究了基于傅里叶叠层成像的光学加密方法和叠层成像水印系统。本项目还研究了基于叠层成像模型的光学密码分析方法。我们发现了光学密码分析模型与叠层成像基本模型的内在联系，从而建立了两个光学密码分析模型。一个是基于二维叠层成像光学攻击模型：对经典双随机相位加密系统的攻击问题转化为二维叠层成像问题，并在已知明文攻击策略下可依据该模型获得上佳的攻击效果。另一个是基于三维叠层成像攻击模型：运用该模型成功攻破了多随机相位级联加密系统。