光学单向散列函数和光学非对称加密技术的研究

One-way Hash functions and asymmetric encryption techniques are important cornerstones of modern cryptography. However, in the field of optical information security, related research has not yet made significant progress. During the study of imaging technology of coherent light passes through scattering mediums, applicant found that: the random nature of the interaction of coherent radiation with the scattering medium, and its random disturbance ability to the passing by light wave front, indicating that it has some natural encryption properties. This project will first study the unique speckle field generated after the interaction between coherent radiation and “multiple” scattering media and extract the features that can characterize the above interaction process, in order to construct an irreversible optical one-way Hash function. On the other hand, it has been confirmed that when coherent radiation is transmitted through a “thin” scattering medium, the target within the memory effect range can be imaged by “calculation”, and if we introduce additional variables (private keys) in the process, this makes it impossible to retrieval to target again without knowing the private key. This is the initial idea of the optical asymmetric encryption system in this project. Further, this project will use specific coherent radiation to successively pass through different types of scattering media, then extract the characteristics of the final speckle pattern, and further comprehensively study its various function which may be equivalent to an optical signature, thereby constructing a secure distribution mechanism for optical keys.

单向散列函数和非对称加密技术是现代密码学的重要基石，而在光学信息安全领域，与之相关的研究至今仍没有取得显著进展。申请人在研究相干散射成像技术时发现：相干辐射与散射介质相互作用的无规特性，以及其对光波前的随机扰乱作用，表明其具有天然的加密属性。本项目将首先研究相干辐射与“多重”散射介质相互作用后生成的独特散斑场，并从中提取出能够表征上述相互作用过程的特征，以期构造出不可逆的光学单向散列函数。另一方面，已经证实：当相干辐射透过“薄”散射介质时，通过“计算”的方式可对记忆效应范围内的目标实现成像，而如若我们在此过程中引入额外变量（私钥），使得在不知道私钥的情况下无法再次成像，这便是本项目关于光学非对称加密系统的初步设想。进一步地，本项目将利用特定相干辐射先后分别经过不同类型散射介质所得最终散斑场的特性，研究其等效的光学签名作用，从而构建出光学密钥的安全分发机制。

本项目以申请人多年在“光学信息安全”领域的的技术积累为基础，结合近年来在“散射成像”领域的新进展，1，创造性地提出并实现了“一种基于光与多重散射介质相互作用的光学散列函数的构造”，并在“并行性”策略的驱动下，引入“偏振调制”，实现了并行光学散列函数的构造；2，系统地研究了经典基于切相傅立叶变换的光学非对称加密的劣势，特别是其安全漏洞，用多种手段对其安全性进行了攻击与分析，与此同时，也引入“生物信息”，提出了安全增强型的非对称加密系统；3，在项目执行的过程中，我们也开展了一些纯粹散射成像方面的工作，期望将来也许能进一步应用到光学信息安全领域。整体而言，在该项目的支撑下，完成了20篇论文（其中SCI论文16篇，基金号第一标注13篇），7个发明专利，先后有10名硕士研究生参与，其中7人已经毕业。