Rajput Sudheesh K, Matoba Osamu
Appl Opt. 2019 Apr 10;58(11):3013-3022. doi: 10.1364/AO.58.003013.
Optical voice encryption based on digital holography (DH), which uses the double random phase encoding (DRPE) in the Fourier transform domain, has been proposed [Opt. Lett.42, 4619 (2017)OPLEDP0146-959210.1364/OL.42.004619]. In the present work, we propose optical voice encryption in other optical domains such as fractional Fourier, Fresnel, and gyrator transform, which convert input information into different mixed space-frequency domains. We also analyze the recording conditions of human voice and some security aspects of the scheme. An optical setup based on off-axis DH is used to record the time-series of holograms, and these holograms can visualize the sound wave propagation. Then, the different encryption domains in double random phase encoding (DRPE) are used to encrypt voice information with enhanced security. With the numerical reconstruction and decryption procedure of DRPE with all correct keys and correct orders of optical domains, the original voice information can be retrieved. The extension of voice encryption in different domains will enhance the security level and analysis of recording, and security aspects will explore the possibilities and challenges of the optical voice encryption scheme. We present simulation results for encryption of an experimentally recorded human voice in various domains.
基于数字全息术（DH）的光学语音加密技术已经被提出，它在傅里叶变换域中使用双随机相位编码（DRPE）[Opt. Lett.42, 4619 (2017)OPLEDP0146-959210.1364/OL.42.004619]。在本工作中，我们提出在其他光学域（如实分数傅里叶、菲涅耳和旋转变换）中进行光学语音加密，这些变换将输入信息转换到不同的混合空间频率域。我们还分析了人类语音的记录条件以及该方案的一些安全方面。基于离轴数字全息术的光学装置用于记录全息图的时间序列，这些全息图可以可视化声波传播。然后，利用双随机相位编码（DRPE）中的不同加密域对语音信息进行加密，以增强安全性。通过使用所有正确密钥和正确光学域顺序的双随机相位编码（DRPE）的数值重建和解密过程，可以检索到原始语音信息。不同域中语音加密的扩展将提高安全级别并对记录进行分析，安全方面将探索光学语音加密方案的可能性和挑战。我们给出了在各个域中对实验记录的人类语音进行加密的模拟结果。
