Chen Yu-Bin, Chen Jia-Shiang
Department of Mechanical Engineering; Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan City 701, Taiwan.
Appl Opt. 2010 Apr 10;49(11):2041-6. doi: 10.1364/AO.49.002041.
A cryptosystem for plaintext messages was developed with gratings and their spectral and directional optical properties. Although there were many applicable grating types and optical responses, this manuscript took an example of a binary metallic surface relief and its specular reflectance at three wavelengths to demonstrate the working principles and the capabilities of the cryptosystem. For one, a series of numbers and the grating characteristics served as the ciphertext containing plaintext messages and the information of the sender's signature. Confidential, high-density, and authentic messages could be, therefore, delivered with tiny or even virtual gratings. Second, four unique encryption/decryption keys here significantly reduced the risk of the ciphertext being easily recovered by eavesdroppers. Further manipulation of keys not only offered several strategies of enhancing the system's safety, but also allowed the coexistence of many two-party, or even multiple-entity, communications. The reflectance spectra shown here were mainly attributed to the Wood's anomaly and were numerically obtained from programs based on rigorous coupled-wave analysis.
利用光栅及其光谱和方向光学特性开发了一种用于明文消息的密码系统。尽管有许多适用的光栅类型和光学响应，但本手稿以二元金属表面浮雕及其在三个波长下的镜面反射率为例，展示了该密码系统的工作原理和能力。一方面，一系列数字和光栅特性用作包含明文消息和发送者签名信息的密文。因此，可以使用微小甚至虚拟的光栅传递机密、高密度和真实的消息。其次，这里的四个独特加密/解密密钥显著降低了密文被窃听者轻易恢复的风险。对密钥的进一步操作不仅提供了几种增强系统安全性的策略，还允许许多双方甚至多实体通信共存。这里所示的反射光谱主要归因于伍德异常，并通过基于严格耦合波分析的程序进行数值计算得到。
