全相位光学图像加密系统的研究
文献类型：学位论文
| 作者 | 顾唯兵 |
| 学位类别 | 硕士 |
| 答辩日期 | 2007 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 何红 |
| 关键词 | 光学图像加密 随机相位 选择密文攻击 全相位 多重图像加密 |
| 其他题名 | Fully phase optical image encryption system |
| 中文摘要 | 近年来，光学图像加密技术的研究引起了人们的广泛关注，并且发展出了许多有效的图像加密技术，取得了很大的进步。这些利用光信息处理技术来实现的光学图像加密技术具有高并行度、高处理速度、大空间带宽及高加密维度等优点，在信息安全领域有着广泛的应用。 本文首先全面总结了光学图像加密技术相关的基本原理、光学装置和应用；对双随机相位加密技术进行了回顾，并对由它发展而来的一些光学图像加密系统作了简单的介绍，指出了它们的优缺点。同时，对传统的双随机相位加密技术的安全性进行了分析，发现在选择密文攻击下，该系统的安全性是不牢固的。攻击者可以通过运用这种攻击方法，获得系统的解密密匙。针对这种情况，我们提出了相应的增强系统安全性的改进措施。 其次，结合现有各种光学图像加密技术的特点，为提高加密系统的安全性和实用性，设计了全相位的光学图像加密系统。该方法利用相位信息来实现光学图像的加密，提高了系统的安全性和图像质量。加/解密过程采用无透镜的菲涅尔衍射，减少了对系统的硬件要求，增强了该技术的实用性。同时在系统中，除了随机相位板外，距离参数和相干照明波长都可以成为系统密匙，从而大大提高了该系统的安全性能和密匙空间。 最后，对于最几年发展而来的多重图像加密技术进行了初步研究，介绍了已有的一些多重图像加密技术，并提出了利用光偏振态的多重图像加密技术。该技术通过调制原图像的偏振态来实现对图像的加密，具有很高的安全性。正确解密后的图像信息，可以通过一检偏器直接获得图像的强度信息。 |
| 英文摘要 | In recent years, optical image encryption techniques for data security have received a great deal of attention. And several successful image encryption techniques have been proposed which made a great deal of progress in many areas. Image encryption technology based on optical information processing technique has the advantages of high parallelism, high-speed, large bandwidth, high spatial dimensions, and has wide application in the field of information security. Firstly, this dissertation focuses on studying of the principle, optical settings and applications about image encryption technique. Also the double random phase encoding technique is looked back and its improved methods are introduced in brief. We also pointed out the advantages and disadvantages in their systems. Meanwhile, we studied the security of the traditional double random phase encryption technique. And found that with chosen ciphertext attacks, an opponent can easily obtain random keys by having repeated access to the decryption machine. However, to enhance the security, we devised some solutions that prevent the attack. Secondly, integrated with the existing optical image encryption features and to enhance the safety and practicality, we proposed a new optical security system of fully phase optical encryption. This technique can improve the optical security and image quality by using fully phase encoded. In the course of encryption and decryption, the system uses fresnel diffraction which is lensless and therefore can minimize the hardware requirement. The distance and the wavelength parameters, as well as the phase code, serve as the key to the system, which significantly enlarge the key space and system security. Finally, we have introduced some multiple-image encryption techniques in brief which are developed in recent years. And we proposed a scheme of multiple-image encryption by using polarized light. This technique can encrypted original image by modulating the polarization which have very high security. After decryption correctly, we can obtain the intensity distribution of decrypted image by polarizer directly. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16476]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 顾唯兵. 全相位光学图像加密系统的研究[D]. 中国科学院上海光学精密机械研究所. 2007. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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