基于双随机相位编码的局部混合光学加密系统  

Local hybrid optical encryption system based on double random phase encoding

作　　者：许祥馨 常军[1] 武楚晗 宋大林[2] Xu Xiang-Xin;Chang Jun;Wu Chu-Han;Song Da-Lin(School of Optoelectronics,Beijing Institute of Technology,Beijing 100081,China;The First Research Institute of the Ministry of Public Security,Beijing 100044,China)

机构地区：[1]北京理工大学光电学院,北京100081 [2]公安部第一研究所,北京100044

出　　处：《物理学报》2020年第20期229-239,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61471039)资助的课题.

摘　　要：针对目前图像的选择性加密无法通过光学结构实现的问题,通过光学设计方法,将基于4f系统的双随机相位编码技术和基于衍射系统的双随机相位编码技术相结合,提出了一种基于双随机相位编码的局部混合光学加密系统.在该系统中,原始图像被分为重要信息和非重要信息,重要信息在4f系统中进行加密,非重要信息在衍射系统中进行加密,用4f系统密文替换掉衍射系统密文中的一部分,得到最终的加密图像.解密为加密的逆过程,将4f系统密文从最终密文中剪切出来后,用其还原出衍射系统密文中被替换掉的信息,从而得到完整的衍射系统密文,两个密文分别经过各自对应系统的逆过程后完成解密.该方法实现了通过光学结构对图像进行选择性加密,安全有效,具有良好的鲁棒性.通过仿真实验验证了该方法的有效性,利用相关系数对该方法的加密和解密效果进行了评估,验证了该方法的安全性.Most of the existing selective encryption schemes are based on image processing and cannot be realized by optical structures,so their practicality is limited.Combining the optical design,a local hybrid optical encryption system based on double random phase encoding is proposed.The system proposed in this paper possesses a common aperture and dual optical path structure,which is widely used in optical design and can effectively improve the practicality of optical encryption system.First,important information and nonimportant information in the original image are separated by a selective beam splitter.Then light waves carrying important information enter into the 4f system for encryption,and light waves carrying non-important information enter into the diffraction system for encryption.Finally,part of the diffraction system ciphertext is replaced with 4f system ciphertext to obtain the final encrypted image.Decryption is the reverse process of encryption.First,the 4f system ciphertext is cut out from the final ciphertext.Then the 4f system ciphertext is used to restore the information replaced in the diffraction system ciphertext,thereby obtaining the complete diffraction system ciphertext.Finally,the two ciphertexts go through the reverse process of their respective systems to complete the decryption.By comparing the statistical characteristics and mean square error of the original image and the encrypted image,the effectiveness of the proposed system's encryption process is proved.By analyzing the peak signal-to-noise ratio of the original image and the decrypted image,the effectiveness of the proposed system's decryption process is proved.The sensitivity of each key of the system is analyzed to prove the security of the system.Especially the system is highly sensitive to selective encryption key,which proves the effectiveness and security of the proposed system for selective encryption.Through simulation,it is verified that the proposed system is very resistant to diffraction attacks.Even if he can obtain all th

关 键 词：光学加密 双随机相位编码 选择性加密 光学设计 

分 类 号：TP309.7[自动化与计算机技术—计算机系统结构]