Abstract In this paper, a novel optical image encryption and authentication scheme based on partial joint power spectrum (JPS) and phase-retrieval technique has been proposed. In the proposed encryption process, a pure amplitude spatial light modulator (SLM) is utilized to modulate and display the entire input plane comprised with the real-valued plaintext and the amplitude key while the random phase mask (RPM) merged with the plaintext could be provided by the ground glass in the practical setup. The entire input plane is regarded as the input of a joint transform correlator (JTC)-based encryption structure while the sub-block (partial JPS) recorded by the charged-couple device (CCD) is the output (ciphertext). Since only the sub-block is recorded in the encryption process, the size of the plaintext could be larger than that of the CCD in a certain degree, which is a major advantage comparing to the conventional JTC-based cryptosystem. In addition, since the size of the ciphertext is irrelative to the size of the plaintext, the security of location key in the entire plane has been enhanced. In addition, the location keys of the chosen sub-block used as the ciphertext are regarded as additional private keys, which enlarges the key spaces of the conventional JTC-based cryptosystem. In the proposed authentication process, the sub-block (ciphertext) is used as the partial amplitude constraint in the iterative process based on phase-retrieval technique and then the decoded image is authenticated by the nonlinear optical verification operator. It is the first time that the optical image encryption and authentication using partial JPS as the ciphertext has been proposed. Numerical simulation is carried out to validate the feasibility and effectiveness of the proposed scheme.

中文翻译：

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基于部分联合功率谱和相位检索技术的光学图像加密与认证方案

摘要 本文提出了一种基于部分联合功率谱(JPS)和相位恢复技术的新型光学图像加密和认证方案。在所提出的加密过程中，使用纯幅度空间光调制器（SLM）来调制和显示由实值明文和幅度密钥组成的整个输入平面，而与明文合并的随机相位掩码（RPM）可以由实际设置中的毛玻璃提供。整个输入平面被视为基于联合变换相关器（JTC）的加密结构的输入，而电荷耦合器件（CCD）记录的子块（部分 JPS）是输出（密文）。由于在加密过程中只记录了子块，明文的大小可以在一定程度上大于CCD的大小，这是与传统的基于JTC的密码系统相比的主要优势。另外，由于密文的大小与明文的大小无关，增强了整个平面位置密钥的安全性。此外，作为密文使用的所选子块的位置密钥被视为额外的私钥，这扩大了传统的基于 JTC 的密码系统的密钥空间。在所提出的认证过程中，在基于相位检索技术的迭代过程中，将子块（密文）作为部分幅度约束，然后通过非线性光学验证算子对解码图像进行认证。首次提出以部分JPS为密文的光学图像加密与认证。进行数值模拟以验证所提出方案的可行性和有效性。