级联双相位密码系统中基于位置复用的双图像加密  

Position-Multiplexing-Based Double-Image Encryption in Cascaded Double-Phase Encoding Cryptosystem

作　　者：秦怡 万玉红[1] 巩琼 Qin Yi;Wan Yuhong;Gong Qiong(Faculty of Science,Beijing University of Technology,Beijing 100124,China;College of Mechanical and Electrical Engineering,Nanyang Normal University,Nanyang 473061,Henan,China)

机构地区：[1]北京工业大学理学部,北京100124 [2]南阳师范学院机电工程学院,河南南阳473061

出　　处：《光学学报》2023年第9期66-77,共12页Acta Optica Sinica

基　　金：国家自然科学基金(61575009,61505091);北京市自然科学基金(4182016)。

摘　　要：级联双相位密码(CDPE)系统是一种包含两个纯相位板(密文板和密钥板)的重要光学密码系统,为了提升该系统的加密效率,提出一种双图像加密方法。加密时,将密钥板的轴向距离作为控制参数,提出一种新的迭代加密算法,该算法可将两幅明文图像加密至同一个密文板中,将传统的CDPE系统的加密效率提升了1倍。解密时,当密钥板分别处于两个设定的轴向位置时,可以在输出平面得到两幅不同的明文图像。采用数值仿真和实验验证了所提方法的有效性,并研究了密钥板两个位置之间的距离对解密结果的影响。对所提方法安全性的分析表明,所提方法对于暴力破解和选择明文攻击均具有稳健性。此外,所提方法可方便地推广至多图像加密,因此CDPE系统的加密效率可以得到进一步提升。Objective Cascaded double-phase encoding(CDPE)is an optical cryptosystem,and it comprises two phase-only masks(ciphertext mask and key mask).Among optical cryptosystems,CDPE is of great importance due to its superiority in security.Its ciphertext is a phase-only mask whose content cannot be directly read out by the intensity-sensitive device such as the charge-coupled device(CCD)or human eyes.Although there is already published research on CDPE,few of them focus on simultaneous compression and encryption.In this paper,we propose a novel iterative encryption algorithm(IEA)to achieve double-image encryption in CDPE,which employs the position of the key mask as a controllable parameter.Compared with that of the traditional CDPE,the encryption capacity of the proposed algorithm has been substantially improved.The proposed algorithm opens up a new way for simultaneous compression and encryption in CDPE,and it may offer new inspiration for the design of other cryptosystems.Methods The optical architecture for decryption in this paper comprises two phase-only masks(ciphertext mask and key mask).Parallel monochromatic light is employed for illumination.The positions of the ciphertext mask and the output plane are fixed during decryption.Two positions along the axis are specified for the key mask.When the key mask locates respectively at these positions,two distinct plaintexts can be individually generated at the output plane.Essentially,the decryption employs two different optical architectures which differ only in the position of the key mask.According to the decryption principle,an IEA is proposed to encrypt the two plaintexts into the ciphertext mask.The IEA requires parallel iteration in the two optical architectures.For each architecture,the light wave virtually illuminates the scheme and finally reaches the output plane after being modulated by the two phase-only masks.At the output plane,the amplitude of the wavefront is replaced with the plaintext.The renewed wavefront at the output plane then propagates back to

关 键 词：图像处理 光学信息安全 双图像加密 位置复用 迭代加密算法 

分 类 号：O438[机械工程—光学工程]